Objective: Solve equations by using multiplication and division. Standard Addressed: J: Show that an equality relationship between two quantities remains the same as long as the same change is made to both quantities; explain how a change in one quantity determines another quantity in a functional relationship. 3.2 Solving Equations by Multiplying and Dividing

Ex. 1

d. 6x = 72 x =12 e. -3 = 15b -5 = b f. -4x = -2.4 x =.6

Ex. 2 a. A store sells 8-foot boards for $2.40 each. What is the cost per foot? 8x = 2.40 X =.30

b. A 10-foot board sells for $3.70. What is the cost per foot? 10x = 3.70 X.37

5x = 540 X = 108 degrees Ex. 3 a. In a regular pentagon, all of the interior angles are equal in measure. The sum of the interior angle measures is 540 degrees. Write and solve an equation to find the measure of each interior angle.

b. In a regular octagon, all of the interior angles are equal in measure. The sum of the interior angle measures is 1080 degrees. Write and solve an equation to find the measure of each interior angle. 8x = 1080 X = 135

Ex. 4

USING RECIPROCALS: Recall that in order to divide by a nonzero number, you multiply by the reciprocal of that number. For example,10 ÷ 5, can be rewritten as 10 ×. The value of both expressions is the same, 2.

Ex. 5

Ex. 6 An apple pie is cut into 6 pieces. Each piece contains a total of 18 grams of fat. Write and solve an equation to determine how many grams of fat are in the whole pie. 1/6 x =