因式分解挖~~ 帮帮忙啊!！

因式分解X^3+Y^3=(X+Y)(X^2-XY+Y^2) 所以最后你应该回了吧
这是个公式，最好记住

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

x+y=1，xy=-1
(x+y)^2=x^2+2xy+y^2=1
x^2+y^2=3

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

x+y=1，xy=-1，(x+y)三次方=1=x3+y3+x2y+y2x+2x2y+2y2x=x3+y3-x-y-2-2=x3+y3-1-2-2

x3+y3=6

先将后式因式分解
X^3+Y^3=(X+Y)(X^2-XY+Y^2)
=(X+Y)[(X+Y)^2-3XY]
将已知代入
=1*(1-(-3))=4

(X+Y)^3=X^3+Y^3+3YX^2+3XY^2=X^3+Y^3+3XY(X+Y)=1
那么x的三次方加y的三次方等于4