Download presentation

1
**Multiplying or Dividing**

Solving Equations by Multiplying or Dividing Warm Up Lesson Presentation Lesson Quiz Holt McDougal Algebra 1 Holt Algebra 1

2
**Warm Up Evaluate each expression. 1. (–7)(2.8) 2. 0.96 ÷ 6 3. (–9)(–9)**

4. 5. 6.

3
Objective Solve one-step equations in one variable by using or .

4
**Inverse Operations Operation Inverse Operation**

Solving an equation that contains or is similar to solving an equation that contains or . Use inverse operations to undo the operations on the . Inverse Operations Operation Inverse Operation

5
**Example 1A: Solving Equations by Using Multiplication**

Solve the equation. –8 = j 3

6
Check It Out! Example 1a Solve the equation. Check your answer. = 10 p 5 Since p is divided by 5, multiply both sides by 5 to undo the division. To check your solution, substitute 50 for p in the original equation.

7
Check It Out! Example 1b Solve the equation. Check your answer. –13 = y 3 Since y is divided by 3, multiply both sides by 3 to undo the division. To check your solution, substitute –39 for y in the original equation.

8
Check It Out! Example 1c Solve the equation. Check your answer. = 7 c 8 Since c is divided by 8, multiply both sides by 8 to undo the division. To check your solution, substitute 56 for c in the original equation.

9
**Example 2A: Solving Equations by Using Division**

Solve the equation. Check your answer. 9y = 108

10
**Example 2B: Solving Equations by Using Division**

Solve the equation. Check your answer. –4.8 = –6v Since v is multiplied by –6, divide both sides by –6 to undo the multiplication.

11
Check It Out! Example 2a Solve the equation. Check your answer. 16 = 4c

12
Check It Out! Example 2b Solve the equation. Check your answer. 0.5y = –10

13
Check It Out! Example 2c Solve the equation. Check your answer. 15k = 75

14
**Remember that dividing is the same as multiplying by the**

Remember that dividing is the same as multiplying by the . When solving equations, you will sometimes find it easier to by a instead of . This is often true when an equation contains .

15
**Example 3A: Solving Equations That Contain Fractions**

Solve the equation. 5 w = 20 6 The reciprocal of is Since w is multiplied by , multiply both sides by 5 6

16
**Example 3B: Solving Equations That Contain Fractions**

Solve the equation. 3 1 8 = z 16 The reciprocal of is 8. Since z is multiplied by , multiply both sides by 8. 1 8 To check your solution, substitute for z in the original equation. 3 2

17
**Solve the equation. Check your answer. 1 4 1 5 – = b**

Check It Out! Example 3a Solve the equation. Check your answer. 1 4 1 5 – = b The reciprocal of is 5. Since b is multiplied by , multiply both sides by 5. 1 5 To check your solution, substitute – for b in the original equation. 5 4

18
Check It Out! Example 3b Solve the equation. = 4j 6 2 3

19
**Check It Out! Example 3b Continued**

Solve the equation. = 4j 6 2 3

20
Check It Out! Example 3c Solve the equation. 1 w = 102 6

21
**one-fourth times earnings equals college fund**

Example 4: Application Ciro puts of the money he earns from mowing lawns into a college education fund. This year Ciro added $285 to his college education fund. Write and solve an equation to find how much money Ciro earned mowing lawns this year. 1 4 one-fourth times earnings equals college fund Write an equation to represent the relationship.

22
**Write an equation to represent the relationship.**

Check it Out! Example 4 The distance in miles from the airport that a plane should begin descending, divided by 3, equals the plane's height above the ground in thousands of feet. A plane began descending 45 miles from the airport. Use the equation to find how high the plane was flying when the descent began. Distance divided by 3 equals height in thousands of feet Write an equation to represent the relationship.

23
**Lesson Quiz: Part 1 1. 2. 3. 8y = 4 4. 126 = 9q 5. 6.**

Solve each equation. 1. 2. 3. 8y = 4 = 9q 5. 6.

24
Lesson Quiz: Part 2 7. A person's weight on Venus is about his or her weight on Earth. Write and solve an equation to find how much a person weighs on Earth if he or she weighs 108 pounds on Venus. 9 10

Similar presentations

© 2020 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google