Warm Up Solve. 1. x + 5 = 9 2. x – 34 = 72 3. 124 = x – 39 x = 4 x = 106 x = 163

Learn to solve one-step equations by using multiplication or division.

Vocabulary Multiplication Property of Equality – you can multiply both sides of an equation by the same number and the statement will still be true Division Property of Equality – you can divide both sides of an equation by the same number and the statement will still be true

• 2 5 10 = 10 5 2 ÷ = Like addition and subtraction, multiplication and division are inverse operations. They “undo” each other. 2 • 5 10 = 10 5 2 ÷ =

If a variable is divided by a number, you can often use multiplication to isolate the variable. Multiply both sides of the equation by the number.

Additional Example 1: Solving an Equation by Multiplication Solve the equation = 13. Check your answer. h 2 h 2 = 13 h 2 (2) = 13(2) Think: h is divided by 2, so multiply both sides by 2 to isolate h. h = 26 Check h 2 = 13 26 2 ? = 13 Substitute 26 for h. 13 = 13 ? 26 is a solution. 

 Check It Out: Example 1 Solve the equation = 30. Check your answer. 5 Solve the equation = 30. Check your answer. x 5 = 30 x 5 (5) = 30(5) Think: x is divided by 5, so multiply both sides by 5 to isolate x. x = 150 Check x 5 = 30 150 5 ? = 30 Substitute 150 for x. 30 = 30 ?  150 is a solution.

You cannot divide by 0. Remember!

If a variable is multiplied by a number, you can often use division to isolate the variable. Divide both sides of the equation by the number.

Additional Example 2: Solving an Equation by Division Solve the equation 51 = 17x. Check your answer. 51 = 17x Think: x is multiplied by 17, so divide both sides by 17 to isolate x. 51 = 17x 17 17 3 = x Check 51 = 17x 51 = 17(3) ? Substitute 3 for x. 51 = 51 ?  3 is a solution.

Check It Out: Example 2 Solve the equation 76 = 19y. Check your answer. 76 = 19y Think: y is multiplied by 19, so divide both sides by 19 to isolate y. 76 = 19y 19 19 4 = y Check 76 = 19y 76 = 19(4) ? Substitute 4 for y. 76 = 76 ?  4 is a solution.

Homework Page 58 #8-18 Even Only

Lesson Quiz: Part I Solve the equation. Check your answer. 1. 12 = 4x 2. 18z = 90 3. 12 = 4. 840 = 12y 5. x = 3; 12 = 4  3 z = 5; 18  5 = 90 x 4 x = 48; 12 = x 4 y = 70; 840 = 12  70 h 22 h = 198; = 9 198 22 = 9