.(x-1)/(x方+3x+2),(5+x)/(x方-x-6),(x-7)/(x方-2x-3)把它们通分

.(x-1)/(x方+3x+2),(5+x)/(x方-x-6),(x-7)/(x方-2x-3)把它们通分
.(x-1)/(x方+3x+2),(5+x)/(x方-x-6),(x-7)/(x方-2x-3)
把它们通分

.(x-1)/(x方+3x+2),(5+x)/(x方-x-6),(x-7)/(x方-2x-3)把它们通分
(x-1)/(x+2)(x+1),(x+5)/(x-3)(x+2),(X-7)/（x-3）（x+1）
通分后分母为(x+1)(x+2)(x-3)
分子为x^2-4x+3,x^2+6x+5,X^2-5x-14