y=(n^2+n)x^2-(2n+1)x+1的因式分解
问题描述：
y=(n^2+n)x^2-(2n+1)x+1的因式分解
答
y=(n^2+n)x^2-(2n+1)x+1
=n(n+1)x^2-(2n+1)x+1
=[(n+1)x-1](nx-1)
=(nx+x-1)(nx-1)