Solve each system by substitution.

8). - 7x-2y=-13

x-2y=11

-7x-2y=-13

x-2y = 11 get x alone

x-2y+2y=11+2y

x = 2y+11 substitute into 1st equation

-7 (2y+11) - 2y = -13

-14y - 77 - 2y = - 13

-16y - 77 = - 13

-16y - 77 + 77 = - 13 + 77

-16y = 64

-16y/-16 = 64/-16

y = - 4

substitute in the 2nd equation

x = 2y + 11

x = 2 (-4) + 11

x = - 3 + 11

x = 3

Check work

-7 (3) - 2 (-4) = - 13

-21 + 8 = - 13

-13 = - 13

3 - 2 (-4) = 11

3 + 8 = 11

11 = 11