5х-3+7х+4=8-15+11х
5х+7х-11х=8-15+3-4
х=-8
ответ: х= -8
(5x-3)+(7x+4)=8-(15-11x)
(5x-3)+(7x+4)-8+15-11x=0
5*x-3+7*x+4-8+15-11*x=0
x+8=0
x=-8
x-6 3