Question

x的平方-y的平方-z的平方+2yz 因式分解

x的3次方+x的平方y-xy的平方-y的3次方
9m的平方-6m+2n-n的平方
x的平方-4+12y-9y的平方
都要做，要过程

Answer 1

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

9m^2-6m+2n-n^2
=9m^2-n^2-6m+2n
=(3m-n)(3m+n)-2(3m-n)
=(3m-n)(3m+n-2)

x^2-4+12y-9y^2
=x^2-(3y-2)^2
=(x+3y-2)(x-3y+2)