Consider the type of equations

5x+y=31

-3x+4y=37

solve the first equation as y in terms of x

like y = ...

You just have to isolate the y term for both equations so the first one would be y=31-5x because you have to subtract x from both sides.

The second one would be y=3+3x and all of that over 4 because to get the y isolated, you have to add 3x to both sides and then divide by 4 to get 4 y to just be y.