计算:(1)(-4a)•(ab2+3a2b-1);(2)(34x6y2+65x3y5-0.9x2y3)÷(-0.6xy).(3)(a2+3)(a-2)-a(a2-2a-2)(4)(2x-y)2-4(x

题目简介

计算:(1)(-4a)•(ab2+3a2b-1);(2)(34x6y2+65x3y5-0.9x2y3)÷(-0.6xy).(3)(a2+3)(a-2)-a(a2-2a-2)(4)(2x-y)2-4(x

题目详情

计算:
(1)(-4a)•(ab2+3a2b-1);
(2)(
3
4
x6y2+
6
5
x3y5-0.9x2y3)÷(-0.6xy).
(3)(a2+3)(a-2)-a(a2-2a-2)
(4)(2x-y)2-4(x-y)(x+2y).
(5)(a+b-1)2
(6)[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]÷4x.
题型:解答题难度:中档来源:不详

答案

(1)原式=-4a•ab2+(-4a)•3a2b+(-4a)•(-1)
=-4a2b2-12a3b+4a.

(2)原式=class="stub"3
4
x6y2÷(-0.6xy)+class="stub"6
5
x3y5÷(-0.6xy)+(-0.9x2y3)÷(-0.6xy)
=-class="stub"5
4
x5y-2x2y4+class="stub"3
2
xy2.

(3)原式=a3-2a2+3a-6-a3+2a2+2a
=5a-6.

(4)原式=4x2-4xy+y2-4x2-8xy+4xy+8y2
=-8xy+9y2.

(5)原式=[(a+b)-1]2
=(a+b)2-2(a+b)+1
=a2+b2+2ab-2a-2b+1.

(6)[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]÷4x
=[9x2-4y2-5x2+2xy-10xy+4y2]÷4x
=(4x2-8xy)÷4x
=x-2y.

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