1. Day 1 (Graphing and Substitution)

2. 2 or more equations with the same set of unknowns We are doing these

3. Graphing Substitution Elimination We are doing these today

4. intersect Intersect once Never intersect Always intersect (same line)

7. Yes, divide every term by 2 They are the same line Infinite solutions

8. 5(- y + 5) + 5y = - 5 -5y +25 + 5y = - 5 25 = - 5 NO No Solution

9. 3x – (4x + 5) = - 15 - x – 5 = - 15 - x = - 10 NO x = 10 PLUG x=10 IN 2y = 4(10) + 5 2y = 45 y = 45/2

10. 2(2y + 1) – 4y = 2 4y + 2 – 4y = 2 2 = 2 INFINITE Infinite solutions

11. Underline important information Determine variables M&M bag = m; Hershey bar = h Set up equations m + h = 6 3m + 2h = 16 Solve m = - h + 6 3m + 2h = 16 3(- h + 6) + 2h = 16 - h + 18 = 16 h=2 and m=4

12. Homework Solve the following systems of equations. Tell whether each has 1 solution, no or infinite solutions. 1. 10x – 2y =6 and y = 5x – 3 2. 2x = y – 3 and 2x + 2y = 21 3. 2x – 4y = 2 and x = 2y +3 4. 5x – 7y =0 and y = 2x 5. 17 cars and trucks get gasoline at the gas station. Each car gets 8 gallons. Each truck gets 19 gallons. The station sells 169 gallons. How many cars were there?