1 7 Solve Equations by Multiplying and Dividing

1 -7 Solve Equations by Multiplying and Dividing

Ch. 1 -7 Solving Equations by Multiplying & Dividing Steps to solve equation or isolate the variable: 1. Move variable if negative by using the addition property of equality 2. If the number you wish to move is multiplied by the variable use the division property of equality 3. If the number you wish is divided by the variable use the multiplication property of equality 4. Simplify 5. Check to see if your answer is correct

Multiplication Property of Equality When you multiply the same number/variable to each side of an equation, the two sides remain equal 5(2) = 10 5(2) x 3 = 10 x 3 30 = 30 -11 = s ÷ 11 -11 x 11 = s ÷ 11 x s -121 = s S÷ 9=5 S÷ 9 x 9=5 x 9 S = 45

Division Property of Equality When you divide the same number/variable to each side of an equation, the two sides remain equal 5 x 2 = 10 5 x 2 / 5 = 10 / 5 2=2 -11 = s x 11 -11 ÷ 11 = s ÷ 11 x 11 -1 = s p x 9 = 36 p ÷ 9 x 9 = 36 ÷ 9 p=4

Solving Equations by Dividing Step 1 You want to isolate the variable Use Di Prop vision ert Equa y of lity Undo multiplication Step 2 Simplify Step 3 ble a i r a e v The positiv t be s u m Check Copyright ©, Long Beach Unified School 1. 8 Solving Equations by Multiplying or Dividing Section District. All rights reserved. - Grade 7

Solving Equations by Dividing Step 1 You want to isolate the variable Use Di Prop vision ert Equa y of lity Undo multiplication Step 2 Simplify Step 3 ble a i r a e v The positiv t be s u m Check Copyright ©, Long Beach Unified School Section 1. 8 Solving Equations by Multiplying or Dividing District. All rights reserved. - Grade 7

Solving Equations by Multiplying Step 1 You want to isolate the variable Undo division U Mult se ipl Prop ication ert Equa y of lity Step 2 Simplify ble a i r a e v The positiv t be s u m Step 3 Check Copyright ©, Long Beach Unified School Section 1. 8 Solving Equations by Multiplying or Dividing District. All rights reserved. - Grade 7

Solving Equations by Multiplying Step 1 You want to isolate the variable Multiply by the reciprocal 10 U Mult se ipl Prop ication ert Equa y of lity Step 2 Simplify Step 3 ble a i r a e v The positiv t be s u m Check Copyright ©, Long Beach Unified School District. All rights reserved. - Section Grade 7 1. 8 Solving Equations by Multiplying or Dividing

Solving Equations by Multiplying Rewrite Step 1 Undo division You want to isolate the variable U Mult se ipl Prop ication ert Equa y of lity Step 2 Simplify Step 3 ble a i r a e v The positiv t be s u m Check Copyright ©, Long Beach Unified School District. All rights reserved. - Grade 7 Section 1. 8 Solving Equations by Multiplying or Dividing

Example 1: Solve each equation by doing the inverse of the operation shown. a. ) -6 y = -30 /-6 y=5 d. ) -12 = 3 m /3 /3 b. ) 5 x = -15 /5 /5 x = -3 e. ) 14 = 2 m /2 /2 -4 = m Rewrite 7 = m Rewrite m = -4 m=7

Example 2: Solve each equation below by doing the inverse of the operation shown. a. ) 2* b. ) -4* *2 Z = -8 d = -24 c. ) d. ) 3 3/2 * * -4 4/1 * * 3/2 * 4/1 1 x = -9 Divide by 2/3, remember that when you divide by a fraction, you multiply by the reciprocal! x = 20 Divide by 1/4, remember that when you divide by a fraction, you multiply by the reciprocal!

Example 3: Determine whether -5 is a solution to the following equations. a. ) 25 v = -5 b. ) -2 t = 10 no c. ) yes d. ) no

Homework n e v e 2 3 2 1 # Pg. 40 ! ! ! S P E T S W O SH