Answer :
28+12x=8x-4 -- move the 8x left and the 28 right
4x=-32 -- divide by 4
x=-8
4x=-32 -- divide by 4
x=-8
[tex] 28+12x=8x-4 \ \ |\ subtract\ 8x\ to\ both\ sides \\ \\ 28+12x-8x=8x-8x-4 \\ \\28+4x=-4 \ \ |\ subtract\ 28\ to\ both\ sides \\\\28-28+4x=-4-28\\\\4x=-32 \ \ | \ divide \ both \ sides\ by\ 4\\\\x=-\frac{32}{4}\\\\x=-8 [/tex]