...You were told that x=4 so when 15 is multiplied by 4 you get an answer of 60 or $60.00 were earned by John for cleaning yards. In the 3rd grade you might have an arithmetic problem which says 43-17=what and the answer is 26, but in Pre-algebra you would be given x-17=26, what is x = to. You must isolate the x or get it by itself. (read more)