Inverse operations

Question

Solve for x and y. Y=550+150x. And Y=400+180x

Answer 1

This is a typical two equation/2 unkown problem

The first gives you a value for y in terms of X

Take the second and everyplace you see Y - substitute the whole equation above

so

550+150x = 400 + 180x

rearrange and solve for X

Plug this value back into equation #1 and solve for y