2×(Х-4)-1,2×(Х+7)=0,4
2X-8-1.2X-8.4=0.4 0.8X=16.8 X=16.8:0.8 X=168:8 X=21
2x-8-1.2x-8.4-0.4=0 0.8x-88.8=0 0.8x=88.8 x=88.8/0.8 x=111