(1)(x-2)(x+1)-x(x-1) =x2-x-2-x2+x =-2.
(2)(x-1)(4-2x)(3-2x) =(-2x2+6x-4)(-2x+3) =4x3-6x2-12x2+18x+8x-12 =4x3-18x2+26x-12.
(3)(2x-3)(3x+2)-2(x+1)(x一1) =6x2+4x-9x-6-2x2+2 =4x2-5x-4.
(4)[ab(1-a)-2a(b-)]•(2a3b2) =[ab-a2b-2ab+a]•(2a3b2) =[-a2b-ab+a]•(2a3b2) =-2a5b3-2a4b3+2a4b2. |