1. Write each equation in slope-intercept form. 1. x-y = 9 2. 2x = 5y 3. 4x + 7y = 14 4. 3x – 1/5y = 6 5. 2.5y + 8.1= 7.5x

2. Lesson 3.1 Solving Systems by Graphing or Substitution

3. System of equations are frequently used to model events that occur in daily life. A system of equations can be used to determine business profits or create exact mixtures.

4. A system of equations is two or more equations with two or more variables. Our goal is to find the x and y values that make both equations true at the same time.

5. Our goal is to find the x and y values that make both equations true at the same time. This is called the solution.

6. Is (3,2) a solution?

7. One solution No SolutionsInfinite Solutions

8. How do we solve a system of equations?  Graphing  Substitution  Elimination

9. Method 1: Graphing Example Graph:

10. Solve by graphing:

13. EXAMPLE 1: y = x + 3 y = 2x – 4

14. 2x + y = 3 3x – 2y = 8

15. The solution is (42,17).The solution is (-3,5,-4). 3t – r =9 -2t + r = 8 x – y –z = -4 5x + 2y -3z = 7 6z = -24

16. Lesson 3.1 Pages 161-162 (5, 6,15,17, 18, 40(a-d), 48, 50, 60-78evens)