BEFORE: September 5, 2017 1. Understand the problem 2. Make a plan 3. Solve BEFORE: September 5, 2017 1. Michelle withdrew $120 from her bank account. She now has $3,345 in her account. Write and solve an equation to find how much money m was in her account before she made the withdrawal. 2. Earth takes 365 days to orbit the Sun. Mars takes 687 days. Write and solve an equation to find how many more days d Mars takes than Earth to orbit the Sun.

DURING: Solving equations by multiplying and dividing Learning Target: I can solve one-step equations in one variable by using multiplicaton or division

Multiplication Property of Equality – states you can multiply the same amount on both sides of an equation and the equation remains true. 4 · 3 = 12 2 · 4 · 3 = 12 · 2 24 = 24 Division Property of Equality – states you can divide the same amount on both sides of an equation and the equation remains true. 2 2 12 = 6 2

7x = 35 Division Property of Equality Multiplication and Division are inverse operations, which means they “undo” each other. To solve an equation, use inverse operations to isolate the variable, or get the variable on one side of the equal sign by itself. 7x = 35 Divide both sides by 7. 7x = 35 Division Property of Equality 7 7 1x = 5 1 · x = x X = 5 Check: 7x = 35 7 (5) = 35 substitute 5 for x 35 = 35 ? true

“I DO” n ÷ 5 = 7

“WE DO” 4. –8 = j 3 4d = 44 x/3 = 18 144 =12h 5. = 7 c 8

“YOU DO” 4. –13 = y 3 9y = 108 -4.8 = -6v 16 = 4c 5. = 10 p 5

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

“I DO” 5 w = 20 6

“WE DO” 1 4 1 5 3 – = b 1 8 = z 16

“YOU DO” 1 w = 102 6

“WE DO” Application 1 Von puts of the money he earns from mowing lawns into a college education fund. This year Von added $285 to his college education fund. Write and solve an equation to find how much money Von earned mowing lawns this year. 4 Von earned $1140 mowing lawns.

“YOU DO” Application 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. The plane was flying at 15,000 ft when the descent began.

Practice Problems You have to show all of your work to get credit!!! Page 27 #1-19 odd