x⁴-a²x²-b²x²+a²b²
=x²(x²-a²)-b²(x²-a²)
=(x²-b²)(x²-a²)
=(x-b)(x+b)(x-a)(x+a)
x²(x+1)-y(xy+x)
=x³+x²-xy²-xy
=x³-xy²+x²-xy
=x(x²-y²)+x(x-y)
=x(x-y)(x+y)+x(x-y)
=x(x-y)(x+y+1)
你有多少题一起出了行吗?我再答被当刷分的封号就不值了.