-2x=2y+5

would you add 2x to the other side?

it depends on what you are trying to solve for. this looks like either a graph or a system of equations. if its a system of equations you need another formula with it in order to tell how to change it. if its a graph you want to solve for y, so you would subtract 5 from both sides and then divide everything by two, so that you could isolate the y.

hope that helps :)