解方程1/(x^2+x-2)+1/(x^2+7x+10=2图片中倒二行怎么化成倒一行的.

Question

解方程1/(x^2+x-2)+1/(x^2+7x+10=2
图片中倒二行怎么化成倒一行的.

Answer 1

就是分式分
1/(n+a)(n+b)=1/(b-a)[1/(n+a)-1/(n+b)]