两道分式加减法计算题:3a-4b/a-b - 11a/a-b + 8a+3b/b-a x^2-10/x-4 + x/4-x + -x+6/4-x

3a-4b/a-b - 11a/a-b + 8a+3b/b-a=（3a-4b-11a-8a-3b）/(a-b)=(-16a-7b)/(a-b)x^2-10/x-4 + x/4-x + -x+6/4-x=(x²-10-x+x-6)/(x-4 )=(x²-16)/(x-4 )=（x+4）（x-4 ）/(x-4 )=x+4我想说。你第一题的8a+3b怎么变成了8a-3b？8a+3b/b-a =(8a+3b)/(b-a) =(-8a-3b)/(a-b)