1. 3.1 Addition Property of Equality (APE)

2. The Addition Property of Equality Rule: if a = b, then a + c = b + c Another Version of the Rule: If a=b, then a+(-c)= b+(-c) Which is the same as: If a=b, then a - c =b - c

3. To solve for “x” x – 8 = 11 Goal: get “ x ” alone on one side of the equation. How: do the opposite of whatever is keeping “ x ” from being all by itself. Why: by doing the opposite operation, the # on the side of the variable cancels out to 0. Rule: whatever you add/subtract to one side of the equation you must add/subtract to the other. x – 8 + 8 = 11 + 8 x = 19

4. Example 1: a - 5 = -2 +5 +5 a = 3

5. Example :2 19 = k + 7 -7 -7 12 = k

6. Example 3: a + 1.5 = 3.2 -1.5 -1.5 a = 1.7

7. Example 4: x + 6.8 =5.2 -6.8 -6.8 __________________ X= -1.6

8. Example 5:

9. Example 6:

10. Example 7 :

11. Example 8: A number is increased by 36 is 15. Find the number. Let x = the original number. x + 36 = 15 - 36 x = -21

12. Example 9: A number decreased by 83 is 46. Find the number. Let x = the original number. x - 83 = 46 +83 x = 129

13. Homework: Page 116 (2-40) even How to set up Homework: 1.Name, period, #, Page#, Problems Assigned 2.Write all questions, signify the answer 3. Show all work by adding/subtracting the same amount to both sides of the equal sign 4. Correct it the next day in class with red pen