1.81x^4-y^42.36a²-(a²+9)²3.(x-y)^3-4(x-y)^2+4(x-y)4.x²-6x+9-
3个回答

1.81x^4-y^4

=(9x^2)^2-(y^2)^2

=(9x^2+y^2)(9x^2-y^2)

=(9x^2+y^2)(3x+y)(3x-y)

2.36a^2-(a^2+9)^2

=(6a+a^2+9)(6a-a^2-9)

=-(a+3)^2(a-3)^2

3.(x-y)^3-4(x-y)^2+4(x-y)

=(x-y)[(x-y)^2-4(x-y)+4].

=(x-y)(x-y-2)^2

4.x^2-6x+9-y^2

=(x-3)^2-y^2

=(x-3+y)(x-3-y)

5.ax-ay+x^2-y^2

=a(x-y)+(x+y)(x-y)

=(x-y)(a+x+y)