Respuesta :

+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!