9x - y = 15 2x + 8y = 28

9x - y = 15

2x + 8y = 28

Use the substitution method.

Solve for y in the first equation.

9x - y = 15

-y = 15 - 9x

y = - 15 + 9x

Now plug in y into the second equation.

2x + 8 (-15 + 9x) = 28

2x - 120 + 72x = 28

74x - 120 = 28

74x = 148

x = 2

Plug x back into the rewritten first equation.

y = - 15 + 9 (2)

y = - 15 + 18

y = 3

x = 2, y = 3