Question

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

Answer 1

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