1. OBJECTIVE I will use inverse operations to correctly solve all of the addition and subtraction equations on independent practice.

2. Vocabulary Inverse Operations - two operations that undo each other Examples: Addition and Subtraction; Multiplication and Division Equivalent Equations - equations that have the same solution or solutions Example: x + 4 = 8 and 2x + 8 = 16

3. Addition Property of Equality Adding the same number to each side of an equation produces an equivalent equation. If x - 4 = 6, then x - 4 + 4 = 6 + 4, or x = 10 If x - a = b, then x - a + a = b + a, or x = b + a

4. Solving an Equation Using Addition x - 12 = 67Original Problem x - 12 + 12 = 67 + 12Add 12 to both sides x = 79Simplify AnswerThe solution is 79. Check x - 12 = 67 79 - 12 = 67 67 = 67

5. Guided Practice 1.x - 9 = -5 2.x - 2 = -13

6. Writing and Solving an Equation The Xbox 360 now sells for $199. This is $50 less than it sold for previously. Write and solve an equation to find the previous cost. Let x be the previous cost.

7. Writing and Solving an Equation (Previous Cost) - (Discount) = (New Cost) Equation x - 50 = 199Substitute x - 50 + 50 = 199 + 50Add x = 249 AnswerThe Xbox 360 previously sold for $249.

8. Subtraction Property of Equality Subtracting the same number from each side of an equation produces an equivalent equation. If x + 4 = 6, then x + 4 - 4 = 6 - 4, or x = 2 If x + a = b, then x + a - a = b - a, or x = b - a

9. x + 14 = 29Original Problem x + 14 -14 = 29 - 14Subtract 14 from both sides x = 15Simplify AnswerThe solution is 15. Check x + 14 = 29 15 + 14 = 29 29 = 29 Solving an Equation Using Subtraction

10. Guided Practice 1.x + 7 = -2 2.x + 4 = 1

11. Writing and Solving an Equation You weigh a llama while it is standing on a trailer. The trailer alone weighs 2345 pounds. The trailer and llama have a combined weight of 3295 pounds. What is the weight of the llama. Let w be the weight of the llama in pounds. Write a verbal model and use it to write and solve an equation.

12. Writing and Solving an Equation Verbal Model (Weight of llama) + (Weight of trailer) = (Combined weight) Equation w + 2345 = 3295Substitute w + 2345 - 2345 = 3295 - 2345Subtract w = 950 AnswerThe weight of the llama is 950 pounds.

13. Independent Practice 1.x - 9 = 2 2.x - 3 = -11 3.x + 9 = 16 4.8 + x = -5