计算:(1)(x-2)(x+1)-x(x-1);(2)(x-1)(4-2x)(3-2x);(3)(2x-3)(3x+2)-2(x+1)(x一1);(4)[ab(1-a)-2a(b-12)]•(2a3b

题目简介

计算:(1)(x-2)(x+1)-x(x-1);(2)(x-1)(4-2x)(3-2x);(3)(2x-3)(3x+2)-2(x+1)(x一1);(4)[ab(1-a)-2a(b-12)]•(2a3b

题目详情

计算:
(1)(x-2)(x+1)-x(x-1);
(2)(x-1)(4-2x)(3-2x);
(3)(2x-3)(3x+2)-2(x+1)(x一1);
(4)[ab(1-a)-2a(b-
1
2
)]•(2a3b2).
题型:解答题难度:中档来源:不详

答案

(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-class="stub"1
2
)]•(2a3b2)
=[ab-a2b-2ab+a]•(2a3b2)
=[-a2b-ab+a]•(2a3b2)
=-2a5b3-2a4b3+2a4b2.

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