2. Solving One Step Equations with Addition and Subtraction Definition: Inverse Operations - Are opposite operations. Adding is the inverse of subtracting and subtracting is the inverse of adding. The goal when solving equations is to isolate the variable. We isolate the variable by completing inverse operation(s). Remember, what you do to one side of the equation you MUST do to the other!

3. Solving One Step Equations with Addition and Subtraction Inverse Actions and Operations What is the inverse of putting items in a box? What is the inverse of tying your shoes? What is the inverse of doing your homework? What is the inverse of multiplication?

4. Solving One Step Equations with Addition Example 1 x + 62 = 93 - 62 - 62 x = 31 Check: x + 62 = 93 Does 31 + 62 = 93? 93 = 93 Subtract 62 from BOTH sides to isolate x. Original equation Solution Check your work to see if your answer is correct! Example 2 81 = 17 + y - 17 – 17___ 64 = y or y = 64 Check: 81 = 17 + y Does 81 = 17 + 64? 81 = 81 Subtract 17 from BOTH sides to isolate y. Original equation Solution Yes, it does Check your work to see if your answer is correct!

5. Solving One Step Equations with Subtraction Example 1 p – 2 = 5 + 2 + 2 p = 7 Check: p - 2 = 5 Does 7 - 2 = 5? 5 = 5 Add 2 to BOTH sides to isolate p. Original equation Solution Example 2 40 = x - 11 40 = x – 11 + 11 51 = x or x = 51 Check: 40 = x - 11 Does 40 = 51 – 11? 40 = 40 Add 11 to BOTH sides to isolate x. Original equation Solution Check your work to see if your answer is correct! Yes, it does Check your work to see if your answer is correct!

6. Solving One Step Equations with Addition and Subtraction Try these: Show all work and check your solutions. 1.) x + 16 = 902.) 21 = a + 13 3.) a - 33 = 494.) 45 = d - 11

7. Solving One Step Equations with Addition and Subtraction Real-Life Application Some surfers recommend that the length of a beginner’s surfboard be 14 inches greater than the surfer’s height. If a surfboard is 82 inches, how tall should the surfer be to ride it? Set up and solve an equation to find the answer.

8. Solving One Step Equations with Addition and Subtraction Real-Life Application When Theodore Roosevelt became president of the United States, he was 42 years old. He was 27 years younger than Ronald Reagan when Reagan became president. How old was Reagan when he became president? Set up and solve an equation to find the answer.