+X= -30 (: All you need to do is distribute 8 to both the X and the 15, which gives you 8X+ 120 = 12X then you have to subtract 8X from itself and 12X You then get 120=4X Divide them, and you get 30 (: I hope you find this useful, and, if so, please mark as brainliest :P Good luck!
