计算1/(x^2-3x+2)+1/(x^2-5x+6)+1/(x^2-4x+3)
问题描述：
计算1/(x^2-3x+2)+1/(x^2-5x+6)+1/(x^2-4x+3)
答
=1/(x-2)(x-1)+1/(x-2)(x-3)+1/(x-3)(x-1)
=(x-3+x-1+x-2)/(x-1)(x-2)(x-3)
=3(x-2)/(x-1)(x-2)(x-3)
=2/(x-1)(x-3)