Solve each system using elimination. 7. 4x+y=8 -3x-y=0 8. 2x+5y=20 2x-5y=3 9. 3x+2y=-10 2x-5y=3

7. 4x+y=8 first equation
(+)
-3x-y=0

x = 8 second equation

substitude second equation into first equation

4(8) + y = 8
32 + y = 8
y = 24

8. 2x+5y=20 first equation
(-)
2x-5y =3

10y = 17
y = 17/10 second equation

substitude second equation into first equation

2x + 5(17/10) = 20
2x + 17/2 = 20
4x + 17 = 40
4x = 23
x = 23/4

9. 3x+2y=-10 (×2) first equation
2x-5y=3 (×3)

6x + 4y = - 20
(-)
6x - 15y = 9

19y = - 29
y = - 29/19 second equation

substitude second equation into first equation

3x + 2(-29/19) = - 10
3x - 58/19 = - 10
3x = - 132/19
x = - 44/19