13
10A Review of index laws 10B Raising a power to another power 10C Negative indices 10D Square roots and cube roots WHAT DO YOU KNOW? 1 List what you know about indices. Create a concept map to show your list. 2 Share what you know with a partner and then with a small group. 3 As a class, create a large concept map that shows your class’s knowledge of indices. OPENING QUESTION If you could count all the stars in the sky, how might you write the number? 10 Digital doc Hungry brain activity Chapter 10 doc-6224 eBook plus eBook plus NUMBER AND ALGEBRA • PATTERNS AND ALGEBRA Indices

10A Review of index laws 10B 10C 10D - Weebly€¦ · 10A Review of index laws 10B Raising a power to another power 10C Negative indices 10D Square roots and cube roots WhAt Do you

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Page 1: 10A Review of index laws 10B 10C 10D - Weebly€¦ · 10A Review of index laws 10B Raising a power to another power 10C Negative indices 10D Square roots and cube roots WhAt Do you

10A Review of index laws10B Raising a power to another power10C Negative indices10D Square roots and cube roots

WhAt Do you knoW?

1 List what you know about indices. Create a concept map to show your list.

2 Share what you know with a partner and then with a small group.

3 As a class, create a large concept map that shows your class’s knowledge of indices.

opening Question

If you could count all the stars in the sky, how might you write the number?

10

Digital docHungry brain activity

Chapter 10doc-6224

Digital docHungry brain activity

Chapter 10doc-6224

eBookpluseBookplus

number AnD AlgebrA • pAtterns AnD AlgebrA

indicesContentsIndicesAre■you■ready?Review■of■index■lawsReview■of■index■lawsRaising■a■power■to■another■powerRaising■a■power■to■another■powerNegative■indicesNegative■indicesSquare■roots■and■cube■rootsSquare■roots■and■cube■rootsSummaryChapter■reviewActivities

Page 2: 10A Review of index laws 10B 10C 10D - Weebly€¦ · 10A Review of index laws 10B Raising a power to another power 10C Negative indices 10D Square roots and cube roots WhAt Do you

number AnD AlgebrA • pAtterns AnD AlgebrA

328 maths Quest 9 for the Australian Curriculum

Are you ready?Try■the■questions■below.■If■you■have■diffi■culty■with■any■of■them,■extra■help■can■be■obtained■by■completing■the■matching■SkillSHEET■located■on■your■eBookPLUS.

Index form 1 State■the■base■and■power■for■each■of■the■following.

a 34 b 25 c 157

Using a calculator to evaluate numbers in index form 2 Calculate■each■of■the■following.

a 24 b 53 c 46

Linking squares with square roots 3 Complete■the■following■statements.

a If■32■=■9,■then■ 9 ■=■.■■.■■. b If■112■=■121,■then■ 121■=■.■■.■■.

c If■172■=■289,■then■ 289 ■=■.■■.■■.

Calculating square roots 4 Calculate■each■of■the■following.

a 64 b 100 c 25

Linking cubes with cube roots 5 Complete■the■following■statements.

a If■23■=■8,■then■ 83 ■=■.■■.■■. b If■53■=■125,■then■ 1253 ■=■.■■.■■.

c If■93■=■729,■then■ 7293 =■.■■.■■.

Calculating cube roots 6 Calculate■each■of■the■following.

a 643 b 2163 c 13

Estimating square roots and cube roots 7 Estimate,■to■the■nearest■whole■number,■the■value■of■each■of■the■following.■(Do■not■use■a■

■calculator.)

a 23 b 102 c 40

d 603 e 113 f 1203

Using a calculator to evaluate square roots and cube roots 8 Use■a■calculator■to■fi■nd■the■value,■correct■to■4■decimal■places,■of■each■square■root■or■cube■root■

in■question■7.

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Digital docSkillSHEET 10.1

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Digital docSkillSHEET 10.5

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Digital docSkillSHEET 10.6

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Digital docSkillSHEET 10.7

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Digital docSkillSHEET 10.8

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Digital docSkillSHEET 10.9

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■ Base■is■3,■power■is■4. Base■is■2,■power■is■5. Base■is■15,■power■is■7.

16 125 4096

■ 3 11

17

■ 8 10 5

■ 2 5

9

■ 4 6 1

■ 5 10 6

4 2 5

a■ 4.7958 b 10.0995 c 6.3246

d 3.9149 e 2.2240 f 4.9324

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number AnD AlgebrA • pAtterns AnD AlgebrA

329Chapter 10 indices

review of index lawsindex notation

■■ The■product■of■factors■can■be■written■in■a■shorter■form■by■using■index■notation.■■ There■are■two■parts:■a■base■and■a■power■(also■called■index,■exponent■or■logarithm).■■ The■base■indicates■what■will■be■multiplied.■■ The■power■(index■or■exponent)■indicates■how■many■times■the■base■will■be■written■and■multiplied■by■itself.

■■ When■written■in■factor■form,■all■the■multiplications■are■shown.■■ When■the■answer■corresponds■to■a■number,■it■is■called■a■basic■numeral.

6 4 = 6 ì 6 ì 6 ì 6= 1296

Power, index, exponentPower, index, exponent

Base

Basic numeral

Factorform

■■ Any■composite■number■can■be■written■as■a■product■of■powers■of■prime■factors■using■a■factor■tree.

100

2 50

2 25

5 5

100 = 2 ì 2 ì 5 ì 5 = 22 ì 52

Express 360 as a product of powers of prime factors using index notation.

think Write

1 Express■360■as■a■product■of■a■factor■pair. 360■=■6■ì■60

2 Determine■whether■each■number■of■the■factor■pair■is■prime.■If■the■factors■are■prime,■no■further■calculations■are■required.■If■the■factors■are■not■prime,■then■each■must■be■expressed■as■a■product■of■another■factor■pair.

■ =■2■ì■3■ì■4■ì15

3 Repeat■step■2■until■each■of■the■factors■is■prime. ■ =■2■ì■3■ì■2■ì■2■ì■3■ì■5

4 Group■the■prime■factors■of■the■same■type■together. ■ =■2■ì■2■ì■2■ì■3■ì■3■ì■5

5 Write■the■answer■using■index■notation.Note:■The■factors■are■generally■expressed■with■bases■in■ascending■order.

360■=■23■ì■32■ì■5

10A

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InteractivityIndex laws

int-2769

WorkeD exAmple 1

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number AnD AlgebrA • pAtterns AnD AlgebrA

330 maths Quest 9 for the Australian Curriculum

multiplication using indices■■ The■First■Index■Law■states:■am■ì■an■=■am +■n

■■ In■algebraic■expressions,■multiply■the■coefficients■of■the■base■number■and■apply■the■First■Index■Law■to■the■pronumeral■indices■separately.

Simplify 5e10 ì 2e3.

think Write

1 Write■the■problem. 5e10■ì■2e3

2 The■order■is■not■important■when■multiplying,■so■place■the■coefficients■first.

=■5■ì■2■ì■e10■ì■e3

3 Multiply■the■coefficients. =■10■ì■e10■ì■e3

4 Check■to■see■if■the■bases■are■the■same.■They■are■both■e.

=■10e10■+■3

5 Simplify■by■using■the■First■Index■Law■(add■the■indices).

=■10e13

■■ When■more■than■one■type■of■base■is■involved,■apply■the■First■Index■Law■to■each■pronumeral■base■separately.

Simplify 7m3 ì 3n5 ì 2m8 ì n4.

think Write

1 Write■the■problem. 7m3■ì■3n5■ì■2m8■ì■n4

2 The■order■is■not■important■when■multiplying,■so■place■coefficients■first■and■group■the■same■pronumerals■together.

=■7■ì■3■ì■2■ì■m3■ì■m8■ì■n5■ì■n4

3 Simplify■by■multiplying■the■coefficients■and■using■the■First■Index■Law■for■bases■that■are■the■same■(add■the■indices).

=■42■ì■m3■+■8■ì■n5■+■4

=■42m11n9

Division using indices■■ The■Second■Index■Law■states:■am■÷■an■=■am − n

■■ In■algebraic■expressions,■divide■the■coefficients■normally■and■apply■the■Second■Index■Law■to■each■base■separately.

WorkeD exAmple 2

WorkeD exAmple 3

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number AnD AlgebrA • pAtterns AnD AlgebrA

331Chapter 10 indices

Simplify 25 8

10 4

6 9

4 5

v w

v w

××

.

think Write

1 Write■the■problem. 25 8

10 4

6 9

4 5

v w

v w

××

2 First■multiply■the■coefficients■in■the■numerator■and■then■the■coefficients■in■the■denominator.■Write■the■pronumerals■as■a■single■term.

= 200

40

6 9

4 5

v w

v w

3 Simplify■by■dividing■the■coefficients■and■applying■the■Second■Index■Law■for■each■pronumeral■separately■(subtract■the■indices).

=5 6 9

14 5

200

40

v w

v w=■5v6■-■4w9■-■5

=■5v2w4

■■ Where■the■coefficients■do■not■divide■evenly,■simplify■by■cancelling.

Simplify 7 4

12

3 8

4

t t

t

×.

think Write

1 Write■the■problem. 7 4

12

3 8

4

t t

t

×

2 Multiply■the■coefficients■in■the■numerator■and■apply■the■First■Index■Law■in■the■numerator.■

= 28

12

11

4

t

t

3 Simplify■the■fraction■formed■and■apply■the■Second■Index■Law■for■the■pronumeral■base.

=7 11

34

28

12

t

t

=−7

3

11 4t

= 73

7t

Zero index■■ Any■base■that■has■an■index■(power)■of■zero■is■equal■to■1.■■ This■is■the■Third■Index■Law:■a0■=■1,■where■a■ò■0.

WorkeD exAmple 4

WorkeD exAmple 5

Page 6: 10A Review of index laws 10B 10C 10D - Weebly€¦ · 10A Review of index laws 10B Raising a power to another power 10C Negative indices 10D Square roots and cube roots WhAt Do you

number AnD AlgebrA • pAtterns AnD AlgebrA

332 maths Quest 9 for the Australian Curriculum

Simplify 9 4

6 2

7 4

3 8

g g

g g

××

.

think Write

1 Write■the■problem.9 4

6 2

7 4

3 8

g g

g g

××

2 First■multiply■the■coefficients■in■the■numerator■and■then■the■coefficients■in■the■denominator.■Then■apply■the■First■Index■Law■in■both■the■numerator■and■denominator.

= 36

12

11

11

g

g

3 Divide■the■coefficients■and■simplify■using■the■Second■Index■Law.

=3 11

111

36

12

g

g

=■3g11■- 11

=■3g0

4 Simplify■using■the■Third■Index■Law. =■3■ì■1=■3

remember

1.■ A■number■written■in■index■form■has■two■parts:■(a)■ a■base,■and(b)■a■power■(index,■exponent■or■logarithm).For■example

6 4 = 6 ì 6 ì 6 ì 6= 1296

Power, index, exponentPower, index, exponent

Base

Basic numeral

Factorform

2.■ The■base■tells■us■what■will■be■multiplied.3.■ The■power■tells■us■how■many■times■the■base■will■be■written■and■multiplied■by■itself.4.■ Factor■form■is■when■all■the■multiplications■are■shown.5.■ When■the■answer■to■a■problem■is■a■number■we■call■it■the■basic■numeral.6.■ Numbers■can■be■written■as■a■product■of■powers■of■prime■numbers.7.■ We■can■add■the■indices■when■multiplying■bases■that■are■the■same.■This■is■known■as■

the■First■Index■Law.■First■Index■Law:■am■ì■an■=■am■+■n

8.■ Whole■number■coefficients■of■the■bases■can■be■multiplied■as■usual.9.■ We■can■subtract■the■indices■when■dividing■bases■that■are■the■same.■This■is■known■as■

the■Second■Index■Law.■Second■Index■Law:■am■ó■an■=■am■-■n

10.■ Any■base■that■has■an■index■(power)■of■zero■is■equal■to■1.■This■is■known■as■the■Third■Index■Law.■Third■Index■Law:■a0■=■1■where■a■ò■0

WorkeD exAmple 6

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number AnD AlgebrA • pAtterns AnD AlgebrA

333Chapter 10 indices

review of index lawsfluenCy

1 We 1 ■Express■each■of■the■following■as■a■product■of■powers■of■prime■factors■using■index■■notation.a 12 b 72 c 75d 240 e 640 f 9800

2 We2 ■Simplify■each■of■the■following.a 4p7■ì■5p4 b 2x 2■ì■3x 6 c 8y6■ì■7y4

d 3p■ì■7p7 e 12t■3■ì■t 2■ì■7t f 6q2■ì■q5■ì■5q8

3 We3 ■Simplify■each■of■the■following.a 2a2■ì■3a4■ì■e3■ì■e4 b 4p3■ì■2h7■ì■h5■ì■p3

c 2m3■ì■5m2■ì■8m4 d 2gh■ì■3g2h5

e 5p4q2■ì■6p2q7 f 8u3w■ì■3uw2■ì■2u5w4

g 9y8d■ì■y5d3■ì■3y4d7 h 7b3c2■ì■2b6c4■ì■3b5c3

i 4r 2s2■ì■3r6s12■ì■2r8s4 j 10h10v2■ì■2h8v6■ì■3h20v12

4 We4 ■Simplify■each■of■the■following.

a15

5

12

8

p

pb

18

3

6

2

r

rc

45

5

5

2

a

a

d6020

7bb

e100

5

10

6

r

rf

9 2qq

5 We5 ■Simplify■each■of■the■following.

a8 3

16

6 4

5

p p

p

×b

12 4

18

5 2

2

b b

b

×c

25 4

15 8

12 7

2

m n

m n

××

d27

12

9 3

2

x y

xye

16

12

7 4

6

h k

h kf

12 6

8 3

8 5

3 2

j f

j f

××

g8 7 2

6 14

3 2p r sp r× ×

×h

27 18 4

18 12 2

9 5 2

4 2

a b c

a b c

× ×× ×

i81 25 16

27 15 12

15 12 34

9 10 30

f g h

f g h

× ×× ×

6 We6 ■Simplify■each■of■the■following.

a2 6

12

3 2

5

a a

a

×b

3 6

9

6 3

9

c c

c

×

c5 10

25

7 5

12

b b

b

×d

8 3

4 3

3 7

5 5

f f

f f

××

e9 4

18

12 10

4 18

k k

k k

××

f2 5

20

4 2

2 2

h k

h k

××

gp q

p

3 4

35

×h

m n

m m

7 3

3 45

××

i8

2 4

9 2

5 4

u v

u u

××

j9 2

3 3

6 12

10 2

x y

y y

××

unDerstAnDing

7 mC ■a■ ■12a8b2c4(de)0f■when■simplifi■ed■is■equal■to:A 12a8b2c4 B 12a8b2c4f C 12a8b2fD 12a8b2 E 12f

exerCise

10A

eBookpluseBookplus

Activity 10-A-1Reviewing the fi rst

four index lawsdoc-4101

Activity 10-A-2Using the fi rst four

index lawsdoc-4102

Activity 10-A-3Applying the fi rst

four index lawsdoc-4103

inDiviDuAl pAthWAys

■ 22■ì■3 23■ì■32 3■ì■52

24■ì■3■ì■5 27■ì■5 23■ì■52■ì■72

■ 20p11 6x8 56y10

21p8 84t6 30q15

■ 6a6e7 8p6h12

80m9 6g3h6

30p6q9 48u9w7

27d11y17 42b14c9

24r16s18 60h38v20

■ 3p4 6r4 9a3

3b6 20r4 9q

32

5p 83

5b 56

10 6m n

9

4

8x y 43

3hk 3j 5f 3

4

3

2p rs 9

2

5 3a b c

203

6 2 4f g h

■ 1 2

2 2

2 h2

2

q4

5

n3

5

v2 2■x6

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number AnD AlgebrA • pAtterns AnD AlgebrA

334 maths Quest 9 for the Australian Curriculum

b 611

2 70

a b

■ì -(3a2b11)0■+■7a0b■when■simplified■is■equal■to:

A 7b B 1■+■7b C -1■+■7ab D -1■+■7b E 6c You■are■told■that■there■is■an■error■in■the■statement■3p7q3r 5s6■=■3p7s6.■To■make■the■

statement■correct,■what■should■the■left-hand■side■be?A (3p7q3r5s6)0 B (3p7)0q3r5s6 C 3p7(q3r5s6)0

D 3p7(q3r5)0s6 E 3(p7q3r5s6)0

d You■are■told■that■there■is■an■error■in■the■statement■8

6

86 7 3

4 2

2

2

f g h

f g h

f

g= .■To■make■the■statement■

correct,■what■should■the■left-hand■side■be?

A8

6

6 7 3 0

0 4 2 0

f g h

f g h

( )

( ) ( )B

8

6

6 7 3 0

4 2 0

( )

( )

f g h

f g hC

8

6

6 7 0 3

4 0 2

( )

( )

f g h

f g h

D8

6

6 7 3

4 2 0

f g h

f g h( )E

8

6

6 7 3 0

4 2 0

f g h

f g h

( )

( )

e What■does■6

4

7 2 8

7 6 0

k m n

k m n( )■equal?■

A 64

B32 C

32

8n

D3

2

2mE

32

2 8m n

raising a power to another power■■ (32)3■can■be■written■as■32■ì■32■ì■32.■■ It■can■then■be■simplified■using■the■First■Index■Law■as■32■+■2■+■2■=■36.From■this,■and■other■similar■examples,■it■can■be■seen■that■(32)3■=■32■ì■3.

■■ The■indices■are■multiplied■when■raising■a■power■to■another■power.This■is■the■Fourth■Index■Law:■(am)n■=■am ì n.

■■ The■Fifth■and■Sixth■Index■Laws■are■variations■of■the■Fourth■Index■Law.Fifth■Index■Law:■(a■ì■b)m■=■am■ì■bm.

Sixth■Index■Law:■ ab

a

b

m m

m

= .

■■ Remember■that■a■base■which■does■not■have■an■index■really■has■an■index■of■1.

Simplify the following.a (74)8 b (3a2b5)3

think Write

a 1 Write■the■problem. a (74)8

2 Simplify■using■the■Fourth■Index■Law■(multiply■the■indices).

=■74 ì 8

=■732

refleCtion 

How do the index laws aid calculations?

10b

WorkeD exAmple 7

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number AnD AlgebrA • pAtterns AnD AlgebrA

335Chapter 10 indices

b 1 Write■the■problem. b (3a2b5)3

2 Simplify■using■the■Fifth■Index■Law■for■each■term■inside■the■brackets■(multiply■the■indices).

=■31 ì 3a2 ì 3b5 ì 3

=■33a6b15

3 Simplify■the■coefficient. =■27a6b15

Simplify (2b5)2 ì (5b8)3.

think Write

1 Write■the■problem.■ (2b5)2■ì■(5b8)3

2 Simplify■using■the■Fifth■Index■Law.■ =■21 ì 2b5 ì 2■ì■51 ì 3b8 ì 3

=■22b10■ì■53b24

3 Calculate■the■coefficient. =■4b10■ì■125b24

=■500b10■ì■b24

=■500b10■+ 24

4 Simplify■using■the■First■Index■Law. =■500b34

Simplify 2 5

2

3a

d

.

think Write

1 Write■the■problem.2 5

2

3a

d

2 Simplify■using■the■Sixth■Index■Law■for■each■term■inside■the■brackets.

=× ×

×21 3 5 3

2 3

a

d

= 23 15

6

a

d

3 Calculate■the■coefficient.■ = 8 15

6

a

d

remember

1.■ When■raising■a■power■to■another■power,■we■multiply■the■indices.■This■is■known■as■the■Fourth■Index■Law.■■Fourth■Index■Law:■(am)n■=■am ì n

2.■ The■Fifth■and■Sixth■Index■Laws■are■really■variations■of■the■Fourth■Index■Law.■Fifth■Index■Law:■(a■ì■b)m■=■am■ì■bm

Sixth■Index■Law:■ab

a

b

m m

m

=

WorkeD exAmple 8

WorkeD exAmple 9

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number AnD AlgebrA • pAtterns AnD AlgebrA

336 maths Quest 9 for the Australian Curriculum

raising a power to another powerfluenCy

1 We 7 ■Simplify■each■of■the■following.a (e2)3 b (f 8)10 c (■p25)4

d (r12)12 e (a2b3)4 f (■pq3)5

g (g3h2)10 h (3w9q2)4 i (7e5r2q4)2

2 We8 ■Simplify■each■of■the■following.a (■p4)2■ì■(q3)2 b (r5)3■ì■(w3)3 c (b5)2■ì■(n3)6

d (■j 6)3■ì■(g4)3 e (q2)2■ì■(r4)5 f (h3)8■ì■(■j2)8

g (■f 4)4■ì■(a7)3 h (t 5)2■ì■(u4)2 i (i3)5■ì■(j2)6

3 We9 ■Simplify■each■of■the■following.

a 3 4

3

2b

d

b 5

2

10

2

2h

j

c 2

3

5

8

3k

t

d 7 9p

8 22

2

q

e 5

3

7

13

3y

z

f

4

7

3

5

4a

c

g −

4

7

2

6

3k

mh

2

3

7

11

4g

h

unDerstAnDing

4 Simplify■each■of■the■following.a (23)4■ì■(24)2 b (t7)3■ì■(t3)4 c (a4)0■ì■(a3)7

d (b6)2■ì■(b4)3 e (e7)8■ì■(e5)2 f (g7)3■ì■(g9)2

g (3a2)4■ì■(2a6)2 h (2d7)3■ì■(3d2)3 i (10r12)4■ì■(2r3)2

5 mC ■What■does■(■p7)2 ó p2■equal?A p7 B p12 C p16

D p4.5 E p

6 mC ■What■does■( ) ( )

( ) ( )

w p

w p

5 2 7 3

2 2 3 5

××

■equal?

A w2p6 B (wp)6 C w14p36

D w2p2 E (wp)3

7 mC ■What■does■(r6)3■ó■(r4)2■equal?A r 3 B r4 C r8 D r 26 E r10

8 Simplify■each■of■the■following.a (a3)4■ó■(a2)3 b (m8)2■ó (m3)4 c (n5)3■ó (n6)2 d (b4)5■ó (b6)2

e (■■f 7)3■ó (■■f■■2)2 f (g8)2■ó (g5)2 g (■p9)3■ó (■p6)3 h (■y4)4■ó (■y7)2

i( )

( )

c

c

6 5

5 2j

( )

( )

f

f

5 3

2 4k

( )

( )

k

k

3 10

2 8l

( )

( )

p

p

12 3

10 2

reAsoning

9 a■ Simplify■each■of■the■following. i (-1)10 ii (-1)7

iii (-1)15 iv (-1)6

b Write■a■general■rule■for■the■result■obtained■when■-1■is■raised■to■a■positive■power.

exerCise

10b

eBookpluseBookplus

Activity 10-B-1Reviewing powers of

powersdoc-4104

Activity 10-B-2Using powers of

powersdoc-4105

Activity 10-B-3Applying powers of

powersdoc-4106

inDiviDuAl pAthWAys

eBookpluseBookplus

Digital docWorkSHEET 10.1

doc-6233

refleCtion   

What difference, if any, is there between the operation of the index laws on numeric terms compared with similar operations on algebraic terms?

■ e6 f 80 p100

r144 a8b12 p5q15

g30h20 81w36q8 49e10r4q8

■ p8q6 r15w9 b10n18

j18g12 q4r 20 h24j16

f 16a21 t10u8 i15j12

■9 8b

d6 25

4

20

4

h

j

8

27

15

24

k

t

49

64

18

44

p

q

125

27

21

39

y

z

256

2401

12

20

a

c

−64

343

6

18

k

m

16

81

28

44

g

h

■ 220 t33 a21

b24 e66 g39

324a20 216d27 40■■000r54

a6 m4 n3 b8

f 17 g6 p9 y2

c20 f 7 k14 p16

(-1)even■=■1■ ■ (-1)odd■=■-1

1 -1 -1 1

Page 11: 10A Review of index laws 10B 10C 10D - Weebly€¦ · 10A Review of index laws 10B Raising a power to another power 10C Negative indices 10D Square roots and cube roots WhAt Do you

number AnD AlgebrA • pAtterns AnD AlgebrA

337Chapter 10 indices

negative indices■■ Using■the■Second■Index■Law,

2

2

3

4 ■=■23■−■4■ Also■ ■2

2

3

4■=■

816

■ =■2−1

■ =■12

It■then■follows■that■2−1■=■12.

This■can■be■generalised■as■a−1■=■1a

.

a Write 3-1 in fractional form b Write 1y

in index form.

think Write

a Use■the■rule■a-1■=■1a

. a 3-1■=■13

b Reverse■the■rule■a-1 = 1a

. b 1y

■=■y-1

■■ This■rule■can■be■extended■for■negative■indices■other■than■−1.For■example,■using■the■Second■Index■Law,

x

x

2

4■=■x2■−■4

■ =■x−2

Also

x

x

2

4■=■

x xx x x x

×× × ×

■ =■12x

It■then■follows■that■x−2■=■12x.

In■general,■a−n■=■1

an.

a Write 4-2 in fractional form. b Write 14a

using a negative index.

think Write

a Use■the■rule■a-n■=■1

an. a 4-2■=■

1

42

■ =■1

16

b Reverse■the■rule■a-n =■1

an. b

14a

■=■a-4

10C

WorkeD exAmple 10

WorkeD exAmple 11

Page 12: 10A Review of index laws 10B 10C 10D - Weebly€¦ · 10A Review of index laws 10B Raising a power to another power 10C Negative indices 10D Square roots and cube roots WhAt Do you

number AnD AlgebrA • pAtterns AnD AlgebrA

338 maths Quest 9 for the Australian Curriculum

remember

1.■ A■negative■index■is■used■to■represent■a■fractional■expression.

2.■ a-1■=■1a

3.■ a-n■=■1

an

negative indicesfluenCy

1 We 10a ■Write■each■of■the■following■in■fractional■form.a 4-1 b 6-1 c m-1 d p-1

2 We 10b ■Write■each■of■the■following■using■a■negative■index.

a 15

b 18

c 1a

d1q

3 We 11a ■Write■each■of■the■following■in■fractional■form.a 5-2 b 2-3 c g-4 d k-6

4 We 11b ■Write■each■of■the■following■using■a■negative■index.

a 1

72b

15y

c14z

d13v

unDerstAnDing

5 Simplify■each■of■the■following■using■only■positive■indices.■(That■is,■if■a■negative■index■appears■in■the■answer,■write■the■answer■in■frac■tional■form.)a x3■ó■x4 b a8■ó■a9

c b

b

4

5d w

w

10

11

6 Simplify■each■of■the■following■giving■your■answer■in■fractional■form.a x5■ó■x8 b y6■ó■y10

c z■ó■z7 d q2■ó■q9

e m0■ó■m4 f 12m3■ó■4m5

g 20

4 2

pq

ph 5

30

2

3

m

m 7 Use■the■index■laws■to■simplify■each■of■the■following.■Express■each■of■your■answers■with■

positive■indices.a a3■ì■a-4 b 12p-2■ì■3p-3

c 7g5h-2■ì■3gh-1 d 4p■ì■5p-2

e s-2■ó■s-3 f 42p2q-3■ó■6p-2qg 6r2■ó■2r-4 h 45a2b-3c■ó■3abc

reAsoning

8 What■is■the■ten’s■digit■of■333?

9 What■is■the■one’s■digit■of■6305?10 What■is■the■one’s■digit■of■81007?

exerCise

10C

eBookpluseBookplus

Activity 10-C-1Reviewing negative

indicesdoc-4107

Activity 10-C-2Using negative

indicesdoc-4108

Activity 10-C-3Applying negative

indicesdoc-4109

inDiviDuAl pAthWAys

refleCtion   

What strategy will you use to remember the index laws?

■14

16 1

m

1p

■ 5-1 8-1 a-1 q-1

■ 125

18

14g

16k

■ 7-2 y-5 z-4 v-3

■1x

1a

1b

1w

■13x

14y

16z

17q

1

4m

32m

5qp

1

6m

21 6

3

g

h

20p

s

3r6 15

4

a

b

8

6

2

1a

7 4

4

p

q

36

5p

Page 13: 10A Review of index laws 10B 10C 10D - Weebly€¦ · 10A Review of index laws 10B Raising a power to another power 10C Negative indices 10D Square roots and cube roots WhAt Do you

2018 Year 10/10A Mathematics v1 & v2 exam structure

Mathematics 10 Mathematics 10A extra questions

Section A

Multiple choice questions

20 questions

(20 marks)

12 questions

(12 marks)

Section B

Short answer questions

10 questions

(50 marks)

7 questions

(28 marks)

Section C

Extended response

3 questions

(30 marks)

3 questions

(30 marks)

Total 100 marks 70 marks

Teachers please note: ● our 10 & 10A exams cover the entire Year 10/10A content ● all exams are emailed in pdf format ● some schools asked about the two versions of our exams, so we would like to clarify: version 1 and version 2 exams consist of completely different questions. ● if you purchased a single version for $100 (say version 1), you will receive two of the following exams:

● 10 exam version 1 ● 10A exam version 1

● if you purchased both versions of exams for $200, you receive all of the following exams:

● 10 exam version 1 ● 10A exam version 1 ● 10 exam version 2 ● 10A exam version 2

● please feel free to modify the time allocated to 10/10A exams if necessary