1. Do Now Rewrite each equation for x. Then rewrite each equation for y. 1. Y + 1 = x 2. 2x + 3y = 6 3. Y + 2x = 3

2. Elimination Method Coordinate Algebra Standard: A.REI.6

3. Essential Question How do I solve a system of equations using the ELIMINATION method?

4. Motivation for the Lesson I am thinking of two numbers whose sum is 30 and whose difference is 10. What are the two numbers? Answers: 20 and 10 Can this riddle be solved using a system of equations?

5. Elimination Method Algebraic Method for solving a system of equations using the sum of like terms to eliminate one of your variables. Looking for opposite coefficients in front of either x or y so they will add to = zero. You must FIND or CREATE opposites!!!

6. Ex 1) Solve by elimination. Answer: (-24, -15)

7. Ex 2) Solve the system using elimination. Answer: ( -1, 2)

8. Ex 3) Solve by Elimination. Answer: no solution

9. Ex 4) Solve by Elimination Answer: infinitely many solutions

10. Ex 5) Word Problems Find two numbers whose sum is 64 and whose difference is 42. Answer: 11 and 53

11. Bonus: Use Elimination twice. Write answer as an ordered triple (x, y, z). Answer: (4, 2, 3)

12. Summarizer Can you give an example of a system of equations in which both variables would be eliminated? What is the solution of your system of equations?

13. Graphic Organizer Let’s walk through it…

14. Homework worksheet