Solve for S: 9s - 5g = -4u
to solve for s you first have to isolate the term with the s in it. in order to get 9s isolated, I need to get rid of, or move, the 5g. to do this I add 5g to both sides.
I've isolated the term with the s in it, now I have to solve for s by dividing by its coefficient, 9.