how do you do substitution with these equations?
700,000 + 5,000x = y
and
600,000 + 10,000x = y
So
600,000 + 10,000x = 700,000 + 5,000x
Solve for x:
10,000x = 100,000 + 5,000x
5,000x = 100,000
x = 20
Plug in x to find y:
700,000 + 5,000(20) = y
700,000 + 100,000 = y
800,000 = y