问题 解答题

计算下列各式:

(1)(-2x2y32•(xy)3

(2)(x+y)(x2-xy+y2

(3)(x+2y-3)(x-2y+3)

(4)(4a2b7+3a3b8-4a2b6)÷(-2ab32

(5)4(x+1)2-2(x+5)(x-5)

答案

(1)原式=4x4y6•x3y3

=4x7y9

(2)原式=x3-x2y+xy2+x2y-xy2+y3

=x3-y3

(3)原式=[x+(2y-3)][x-(2y-3)]

=x2-(2y-3)2

=x2-4y2+12y-9.

(4)原式=(4a2b7+3a3b8-4a2b6)÷4a2b6

=b+

3
4
ab2-1.

(5)原式=4x2+8x+4-2x2+50

=2x2+8x+54.

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