how to factorize?

185y3 + 320(x3﹣y3)

= 320x3﹣135y3

= 5 (64x3﹣27y3)

= 5 [(4x)3﹣(3y)3]

= 5 (4x﹣3y)[(4x)2 + (4x)(3y) + (3y)2]

= 5 (4x﹣3y) (16x2 + 12xy + 9y2)
利用恆等式a3﹣b3 = (a﹣b)(a2 + ab + b2)

2008-02-12 18:31:02 補充：
185y^3+320(x^3﹣y^3)=185y^3+320x^3﹣320y^3 ←首先展開，然後合併同類項，才能因式分解。

185y^3 + 320(x^3 - y^3)
= 185y^3 + 320x^3 - 320y^3
= 320x^3 - 135y^3
= 5(64x^3 - 27y^3)
= 5((4x)^3 - (3y)^3)
= 5(4x - 3 y)(16x^2 + 12xy + 9y^2)

185y^3+320(x^3-y^3)
=185y^3+320x^3-320y^3
=320x^3-135y^3
=5(64x^3-27y^3)
=5[(4x)^3-(3y)^3]
=5(4x-3y)[(4x)^2+(4x)(3y)+(3y)^2]
=5(4x-3y)(16x^2+12xy+9y^2)