LESSON 5.7SOLVING TWO-STEP EQUATIONS

Objective: Students will be able to write and solve two-step equations with one variable!

11 + 3P = -1

b – 2 = 14

2.6 + 4r = 9.2

In Lesson 5.3-5.6 you solved one-step equations by using a single inverse (or opposite) operation.

The inverse operation of addition is _________.

The inverse operation of subtraction is _______.

The inverse operation of multiplication is_________.

The inverse operation of division is ____________.

subtractionaddition

divisionmultiplication

d + 4 = -9

r - 18 = -26 4y=32

a = -3

7

- 4 -4

d = -13

+18 +18 r = -8 4 4

y = 8

X7 X7

a = -21: :

SOLVING TWO-STEP EQUATIONS

2x + 5 = -3What is on the same side of the equal sign as the variable x ? And what mathematical operations are being done to the variable?

Rule #1: ALWAYS UNDO ADDITION OR SUBTRACTION FIRST (This turns your equation into a one-step equation.)

- 5 -52x = -8

Rule #2: Undo Multiplication or division after addition or subtraction!!!!

Now you have created a one-step equation which you already know how to solve!

2 2::

:X = -4

Check your answer!2(-4) + 5 = -3

-8 + 5 = -3-3 = -3

You Did It!Your turn:-5x + 7= -3What is on

the same side of the equal sign as the variable x ?

And what mathematical operations are being done to the variable x ? What mathematical operation do you do the inverse of

first?

- 7 -7

-5x = -10

HEY! NOW IT IS A ONE-STEP EQUATION

WHICH YOU KNOW HOW TO

SOLVE!

-5 -5

: :x = 2

Check: -5 (2) + 7 = -3-10 + 7 = -3

-3=-3Yeah!

LET’S PRACTICE A FEW

DO: PRACTICE 5.7