1. Key Concepts for Sect. 7.1 *A system of equations is two or more equations in two or more variables. *Numerically, a solution to a system of equations is an ordered pair that satisfies each equation. *Graphically, a solution to a system of equations is the point of intersection of the graphs of the equations.

2. Guided Practice for Sect. 7.1 Ex 1:Find the solution to each system of equations by using elimination (linear combinations). a)x + 3y = 1 -x + 2y = 4

3. Guided Practice for Sect. 7.1 Ex 2:Find the solution to each system of equations by using elimination (linear combinations). a)2x - y = 3 4x + 3y = 21

4. On Your Own Find the solution to each system of equations by using elimination (linear combinations). a)2x + 3y = 5 -3x + 5y = 21

5. Answer: a)(-2, 3)

6. Guided Practice for Sect. 7.1 Ex 3:Find the solution to the system of equations by using the substitution method. a)x = y - 4 x + 2y = 5

7. b)x = -2y + 1 5x - 4y = -23

8. Guided Practice for Sect. 7.1 Ex 4:Find the solution to the system of equations by using the substitution method. a)-2x + y = -5 x 2 + y 2 = 25

9. b)x + y = 0 x 3 - 5x - y = 0

10. On Your Own Find the solution to the system of equations by using the substitution method. a)2x 2 + y = 3 x + y = -4

11. Answer: a)(-1.6, -2.4) and (2.1, -6.1)

12. Guided Practice for Sect. 7.1 Ex 5:Use a graphing calculator to find the solution to the system of equations. a)x - y = -4 x + 2y = 5

13. Guided Practice for Sect. 7.1 Ex 6:Use a graphing calculator to find the solution to the system of equations. a)-2x + y = -5 x 2 + y 2 = 25

14. b)x + y = 0 x 3 - 5x - y = 0