Lesson 3.2, For use with pages 122-126

Solve the equation using mental math.

1. 5m = 35 2. t ÷ 11 = 10

Lesson 3.2, For use with pages 122-126

Solve the equation using mental math.

1. 5m = 35

ANSWER 7

2. t ÷ 11 = 10

ANSWER 110

Solving Equations Using Multiplication & Division Transformations

Section 3.2 Page 122

All of the equations we have solved so far have been in the form of:

3 + x = -5

Now we will look at equations in the form of: 3x = -9 2/3 x = 18

-2/5 x = -6/7Notice how they are “connected” to the

variable. (by what operation?)

Properties of Equality

Multiplication Property of Equality If a = b, then ca = cb

Division Property of Equality If a = b, then a = b c c c = 0

Just like addition and subtraction transformations, what ever you do to one side of the equation, you MUST do to the other.

If you multiply one side by two, you must multiply the other side by two.

Solve: -3x = 15

-3x = 15 divide by -3

-3 -3

x = -5 simplify

Note: do NOT use division sign – use fraction bar to represent division.

Solving Equations Using Multiplication & Division Transformations

Solve: -3x = 15

-3x = 15 You could also Mult by – 1/3(-1/3) (-3x) = 15 (-1/3) 1x = -5 x = -5

Is dividing by -3 the same thing as multiplying by -1/3?

YES!!

-3x = - 8

-3x = - 8

-3 -3 divide by -3

x = + 8/3 or 2 2/3

Solving Equations Using Multiplication & Division Transformations

-12x = - 60

-12x = - 60

-12 -12 divide by -12

x = 5

Solving Equations Using Multiplication & Division Transformations

Solve each equation

204

x = −

Is x/4 the same as 1/4x?

68

x =

Solve each equation

155

y = −−

Solve each equation

1 3

7 8x = −

714

8x=

A movie theater has 1025 seats. Each row has 25 seats. How many rows are there in the theater?

x = # of rows ( identify variable)

25x = 1025 write equation

25 25

x = 41 rows solve /label

The average charge in value of a company’s high-resolution graphic printer is -$150 per month. How many months later is the value relative to the original cost of -$1200?

x = # months later -150x = -1200

-150 -150 x = 8 months later

Assignment : P. 124 10-22 evens,43-46 43-46 x = identify varible

write equation Solve – answer questions You must show ALL the steps to solve

on your paper. Having only the answer will NOT be counted correct.

Check mentally to make sure your answer is correct.