参考一下
如图
如图
(28)
x^4-2x^2+1
=(x^2-1)^2
=[(x-1)(x+1)]^2
(29)
x^4-8x^2.y^2+16y^2
=(x^2-4y^2)^2
=[(x-2y)(x+2y)]^2
(30)
2x^2+8x+8
=2(x^2+4x+4)
=2(x+2)^2
(31)
x^3.y-xy
=xy(x^2-1)
=xy(x-1)(x+1)
(32)
3x-12x^3
=3x(1-4x^2)
=3x(1-2x)(1+2x)
(33)
x^2.y-2xy^2+y^3
=y(x^2-2xy +y^2)
=y(x-y)^2