分式加减题.

题目

分式加减题.
(1X-3)-(1X^2-9)-(X-16-2X)=?
(5X^-2X)-(4X^2+2X)-(3X^2-4)=?
过后追分~
555

答案

1/(x-3)-1/(x^2-9)-(x-1)/(6-2x)=1/(x-3)-1/((x+3)(x-3))-(x-1)/(2(3-x))=1/(x-3)-1/((x+3)(x-3))+(x-1)/(2(x-3))分子,分母各乘以2(x-3)(x+3)=2(x+3)-2+(x-1)(x+3)=2x+6-2+x^2+2x-3=x^2+4x+3=(x+1)(x+3)第二题看不懂...