问题
解答题
计算下列各式:
(1)(-2x2y3)2•(xy)3
(2)(x+y)(x2-xy+y2)
(3)(x+2y-3)(x-2y+3)
(4)(4a2b7+3a3b8-4a2b6)÷(-2ab3)2
(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+
ab2-1.3 4
(5)原式=4x2+8x+4-2x2+50
=2x2+8x+54.