2-8 Multiplication Equations Warm Up Warm Up Lesson Presentation Lesson Presentation Problem of the Day Problem of the Day Lesson Quizzes Lesson Quizzes

2-8 Multiplication Equations Warm Up Divide

2-8 Multiplication Equations Problem of the Day Katie’s little brother is building a tower with blocks. He adds 6 blocks and then removes 4 blocks. If he adds 8 more blocks, the tower will have twice as many blocks as when he started. How many blocks did he start with? 10 blocks

2-8 Multiplication Equations MA.6.A.3.2 Write [and] solve…one-step linear equations… Sunshine State Standards

2-8 Multiplication Equations Multiplication and division are inverse operations. To solve an equation that contains multiplication, use division to “undo” the multiplication. 4m = m = 8 Caution ! 4m means “4  m.”

2-8 Multiplication Equations 5p = 75p is multiplied by 5. 5 p = 15 Divide both sides by 5 to undo the multiplication. Check 5p = 75 Substitute 15 for p in the equation. Solve the equation. Check your answer. 15 is the solution. 75 = 75 ? Additional Example 1A: Solving Multiplication Equations 5(15)= 75 ? 5 5p = 75

2-8 Multiplication Equations 16 = 8rr is multiplied by = r Divide both sides by 8 to undo the multiplication. Check 16 = 8r Substitute 2 for r in the equation. Solve the equation. Check your answer. 2 is the solution. 16 = 16 ? Additional Example 1B: Solving Multiplication Equations 16 = 8(2) ? 8 16 = 8r

2-8 Multiplication Equations Check It Out: 1 Solve the equation. Check your answer. 8a = 72 a = 9

2-8 Multiplication Equations The area of a rectangle is 56 square inches. Its length is 8 inches. What is its width? Additional Example 2: Problem Solving Application

2-8 Multiplication Equations Additional Example 2 Continued 1 Understand the Problem The answer will be the width of the rectangle in inches. List the important information: The area of the rectangle is 56 square inches. The length of the rectangle is 8 inches. Draw a diagram to represent this information w

2-8 Multiplication Equations Additional Example 2 Continued 2 Make a Plan You can write and solve an equation using the formula for area. To find the area of a rectangle, multiply its length by its width. w l A = l w 56 = 8w

2-8 Multiplication Equations Additional Example 2 Continued 56 = 8w Solve = w So the width of the rectangle is 7 inches. w is multiplied by 8. Divide both sides by 8 to undo the multiplication.

2-8 Multiplication Equations Additional Example 2 Continued Look Back Arrange 56 identical squares in a rectangle. The length is 8, so line up the squares in rows of 8. You can make 7 rows of 8, so the width of the rectangle is 7. 4

2-8 Multiplication Equations Check It Out: Example 2 The area of a rectangle is 48 square inches. Its width is 6 inches. What is its length?

2-8 Multiplication Equations Check It Out: Example 2 continued 1 Understand the Problem Draw a diagram to represent the important information. 48 l 6

2-8 Multiplication Equations Check It Out: Example 2 Continued 2 Make a Plan w l A = l w 48 = 6 l

2-8 Multiplication Equations Check It Out: Example 2 Continued 48 = 6 l Solve = l So the length of the rectangle is 8 inches. l is multiplied by 6. Divide both sides by 6 to undo the multiplication.

2-8 Multiplication Equations Check It Out: Example 2 Continued Look Back Arrange 48 identical squares in a rectangle. The width is 6, so line up the squares in columns of 6. You can make 8 columns of 6, so the length of the rectangle is 8. 4