Question

帮我做做下面几道题,a-a^3x^3-xy^34x^3y^3-9xy4x^2-8x-12y-9y^2已知a^2+b^2=

Answer 1

a-a^3

=a(1-a^2)

=a(1+a)(1-a)

x^3y-xy^3

=x(x^2-y^2)

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

4x^3y^3-9xy

=xy(4x^2y^2-9)

=xy(2xy+3)(2xy-3)

4x^2-8x-12y-9y^2

=4x^2-8x+4-(9y^2+12y+4)

=4(x-1)^2-(3y+2)^2

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

=(2x+3y)(2x-3y-4)