GOAL 1USING TWO OR MORE TRANSFORMATIONS

3.3 Solving Multi-Step Equations

EXAMPLE 1

1. Simplify each side of the equation first.

2. Perform inverse operations in reverse order.

SOLVING MULTI-STEP EQUATIONS

Extra Example 1

EXAMPLE 2

Solve:

15 10

2x

Click to see the solution

Extra Example 2Solve:

2x – 9x + 17 = –4

Click to see the solution

Checkpoint Solve

2 19 1

5 5x x

EXAMPLE 3

x = –50

Extra Example 3Solve

4x + 12(x – 3) = 28

EXAMPLE 4

Click to see the solution

Extra Example 4Solve

2x – 5(x – 9) = 27

Click to see the solution

CheckpointSolve

10x – 6(2x + 5) = 20

EXAMPLE 5

x = –25

Extra Example 5

Solve

312 2

10x

Click to see the solution

Checkpoint

Solve

424 7

3x

x = –11

GOAL 2 SOLVING REAL-LIFE PROBLEMS

We will look at some specific real-life problems to learn how to write multi-step equations which can then be solved.

3.3 Solving Multi-Step Equations

EXAMPLE 6

Extra Example 6What Celsius temperature would indicate a fever of 104°F?

Use the formula 9

32.5

F C

Click to see the solution

Checkpoint

Use to convert 212°F to Celsius.9

325

F C

EXAMPLE 7

C = 100

Extra Example 7Air temperature drops about 3°F for each 1000 ft increase in altitude. If the air temperature at sea level is 77°F, at what altitude would you expect the temperature to be 53°F?

Click to see the solution

CheckpointThe speed of a falling object increases 32 ft/sec for each second it falls. How many seconds will it take the speed of a rock dropped from a very high cliff to increase from 50 ft/sec to 210 ft/sec?

t = 5 sec

Example 8The sum of three numbers is 67. The second number is 4 more than three times the first number. The third number is three less than two times the first number. Find the three numbers.

Click to see the solution

QUESTIONS?