括号2x减一括号的平方=1解：2x-1=士1 2x=2或0 x=1或0
3x(x²-2x+1)-2x²(x-1)=3x(x-1)²-2x²(x-1)=(x-1)[3x(x-1)-2x²]=(x-1)(3x²-3x-2x²)=(x-1)(x²-3x)=x(x-1)(x-3)
图
如图
