第90页练习第1题答案
解:(1)原式=x3 +2x2+1/2x
=2x2-4x-1
=x3-7/2x-1
(2)原式=a3 -a2 b+ab2-a× b+ab2-b3
=a3 -2a2b+2ab2-b3
(3)原式=(6x2 -15x- 4x+10)(x+1)
= (6x2 -19x+10)(x+1)
=6x3 -19x2+10x+ 6x2-19x+ 10
=6x3-13x2 -9x+10
(4)原式=(x+y)(x2-2xy+y2)
=x3-2x2 y+xy2+ x2y- 2xy2+ y3
=x3 -x2 y-xy2 +y3