y = 3x + 4
x + y = 8
Substitute 3x + 4 in for y in the second equation.
x + 3x + 4 = 8
Combine like terms.
4x + 4 = 8
Subtract 4 from both sides.
4x = 4
Divide 4 off of both sides to find the value of x.
x = 1
Now plug 1 into the second equation for x.
1 + y = 8
Subtract 1 from both sides.
y = 7
(1,7) is the final answer.
