3-2 HW: Pg. 144-146 #4-34e, 38, 40, 46-47

46.) B 47.) C

Solve an equation by combining like termsEXAMPLE 1

Solve 8x – 3x – 10 = 20.

5x – 10 = 20 Combine like terms.

+ 10 + 10 Add 10 to each side.

5x = 30Simplify.

Divide each side by 5.

x = 6 Simplify.

55

EXAMPLE 2 Solve an equation using the distributive property

Solve 7x + 2(x + 6) = 39.

SOLUTION

Show All Steps

7x + 2(x + 6) = 39

7x + 2x + 12 = 39

9x + 12 = 39

– 12 – 12

x = 3

=9x9

279

Standardized Test PracticeEXAMPLE 3

ANSWER

The correct answer is D. A C DB

SOLUTION

In Step 2, the distributive property is used to simplify the left side of the equation. Because –4(x – 3) = –4x + 12, Step 2 should be 5x – 4x + 12 = 17.

GUIDED PRACTICE for Examples 1, 2, and 3

9d – 2d + 4 = 321.

Solve the equation. Check your solution.

4ANSWER

2w + 3(w + 4) = 272. 3ANSWER

6x – 2(x – 5) = 463. 9ANSWER

Multiply by a reciprocal to solve an equationEXAMPLE 4

23

32

(3x + 5) = (–24)23

Multiply each side by , the reciprocal of .

233

2

3x + 5 = –16 Simplify.

3x = –21

Subtract 5 from each side.

x = –7

Divide each side by 3.

32

(3x + 5) = –24Solve .

-5 -5

3 3

Multiply by a reciprocal to solve an equation EXAMPLE 4GUIDED PRACTICE for Example 4

34

(z – 6) = 124.

Solve the equation. Check your solution.

22ANSWER

6. 45

(4a – 1) = 28– –8.5ANSWER

25

(3r + 4) = 105. 7ANSWER

Write and solve an equation EXAMPLE 5

A flock of cranes migrates from Canada to Texas. The cranes take 14 days (336 hours) to travel 2500 miles. The cranes fly at an average speed of 25 miles per hour. How many hours of the migration are the cranes not flying?

BIRD MIGRATION

SOLUTION Let x be the amount of time the cranes are not flying. Then 336 – x is the amount of time they are flying.

2500 = 25 (336 – x)

EXAMPLE 5

2500 = 25(336 – x) Write equation.

2500 = 8400 – 25x Distributive property

–5900 = –25x

Subtract 8400 from each side.

236 = x

Divide each side by –25.

ANSWER

The cranes were not flying for 236 hours of the migration.

Write and solve an equation

-8400 -8400

-25 -25

EXAMPLE 5 Write and solve an equationGUIDED PRACTICE for Example 5

7. WHAT IF? Suppose the cranes take 12 days (288 hours) to travel the 2500 miles. How many hours of this migration are the cranes not flying?

188 hANSWER

Summary• How do you solve multi-step equations?• ANS: Simplify 1 or both sides, then use inverse

operations to get variable by itself.• How do you deal with a problem that has a

fraction being distributed to 2 terms on one side?• ANS: multiply by the reciprocal on both sides

first.• What is wrong with this problem:

35𝑥− 4=18

x - 4=30 +4 +4 x = 34

Check Yourself

Pg. 150-153 #4-16eoe,18-28e,38, 44-45 & Quiz 1 Pg. 153 #1-13 to prepare for

Chapter 3 Quiz 1 next class