1-4 Solving Multiplication and Division Equations Warm Up: Solve. Pre-Algebra Warm Up: Solve. 1. x  1 = 9 x = 10 n = 12 2. 16 = n + 4 3. The temperature was 88° in the afternoon and decreased by d° until it was 62° in the evening. How much did the temp go down? d = 26° decrease 4. To solve a one-step addition or subtraction problem we do the _______ of what is already happening in the equation. opposite

Learn to solve equations using multiplication and division.

Yesterday you solved addition and subtraction problems by doing the opposite of what was happening in the problem. We can solve a multiplication or division problem the same way!

Example 1: Solving One-Step Equations Solve 8x = 32. 8x = 32 Find the letter and the number next to it. 8x = 32 The 8 and x are multiplying, so we need to do the OPPOSITE! 8 8 1x = 4 Divide both sides by 8. x = 4 Check 8x = 32 Check your answer by plugging in the number you got for x. 8(4) = 32 32 = 32

Example 2: Solving One-Step Equations Find the letter and the number next to it. n 7 Solve = 7. n 7 = 7 7 • 7 • The n and 7 are dividing, so we need to do the OPPOSITE! n = 49 Multiply both sides by 7. Check n 7 = 7 Check your answer by plugging in the number you got for x. 49 7 = 7 7 = 7

Partner Examples 3 and 4: n 2 Solve 9x = 36. Solve = 8 n 2 = 8 9x = 36 2 • 2 • 9x = 36 n = 16 9 9 1x = 4 Check x = 4 n 2 = 8 Check 16 2 = 8 9x = 36 8 = 8 9(4) = 36 36 = 36

= =  • Example 5: Story Problem 3 p 63 3p = 63 3 3 p = 21 Megan is making a scrapbook of her pictures. She wants to put 3 pictures on each page. She has 63 photos. Write and solve an equation to find how many pages she will need for all the photos. Number of pictures per page  Number of pages in the book = Total number of photos she has • = 3 p 63 3p = 63 Write the equation (Multiplying). 3 3 Opposite: Divide both sides by 3. p = 21 Megan needs 21 pages in her scrapbook.

= = • Example 6: Story Problem  1 x 50 8 1 x = 50 8 1 8 • x = 50 8 • Jordan already has $50 to help pay for a new snowboard. That is only one-eighth of how much money he needs. How much money does a snowboard cost? Fraction of total $ amount he has Total cost of the skateboard = Amount of money he has so far  1 8 • = x 50 x = 50 1 8 Write the equation (Dividing). x = 50 1 8 8 • 8 • Opposite: Multiply both sides by 8. x = $400 Jordan needs a total of $400 to buy the skateboard