3x+x(1-(2x+3))=8(x-2)+12-2x²
3x+x(1-2x-3)=8x-16+12-2x²
3x+x-2x²-3x=8x-16+12-2x²
3x+x-2x²-3x-8x+2x²=-16+12
-7x=-4
x=4/7
ответ:x=4/7
3x+x(1-(2x+3))=8(x-2)+12-2x²
3x+x(1-2x-3)=8x-16+12-2x²
3x+x-2x²-3x=8x-16+12-2x²
3x+x-2x²-3x-8x+2x²=-16+12
-7x=-4
x=4/7
ответ:x=4/7