1. Math 1-9: Warm-up Solve each equation. Check your solution.
-3 + b = -7
c – 13 = 2
3. x + |-4| = 9
28 = b
Write and solve an equation to find the number.
If you increase a number by 9, the result is 26.
Jacob opened a checking account with $200. Then he wrote a check for $125. What is the current balance in Jacob’s checking account?
A. -$33 B. $75 C. $325 D. $83

2. Math 1-9: Solving Multiplication and Division Equations
Objective: How to solve equations by using the Division and Multiplication Properties of Equality.

3. Vocabulary
Review:
identity property (x) – the product of a number and 1 is that same number

4. Properties Multiplication Property of Equality
if you multiply each side of an equation by the same number, the two sides remain equal.
7 = 7
7(-3) = 7(-3)
-21 = -21
Division Property of Equality
if you divide each side of an equation by the same nonzero number, the two sides remain equal.
25 = 25
5 = 5

5. What you do to one side… you must do to the other!
Golden Rule:
What you do to one side… you must do to the other!

6. Remember…
…your goal is to get the variable by itself on one side of the equal sign
isolating the variable
…to look at the side of the equation with a variable first and “undo” that operation
inverse operation

7. Examples Solve 19w = 104. Check your solution.
19w = write the equation
divide each side by 19
1w = ÷19=1 and 114÷19=6
w = 6 w is by itself, identity property 1w=w
Check: 19w = 114 write the equation
19(6) ? 114 replace w with 6 –> is it true?
114 = 114  26+19=45

8. Examples Solve . Check your solution. write the equation
multiply each side by 15
d = d is by itself
Check: write the equation
replace d with -135 –> is it true?
-9 = -9  -135÷15=-9

9. Practice
7z = -49
-2d = -12 3. 4.

10. Assignment Pg. 52 (14-34e; 30ec) Quiz: Lessons 6-9  9/4
Celebration of Knowledge:
Chapter 1  9/9