Question

分式的加减法计算（要过程）

（1）3a+2b\5a²b + a+b\5a²b - b-a\5a²b （2）m+2n\n-m - n\m-n + 2m\n-m
（3）1\a+3 + 6\a²-9 （4）1\x-3 + 1-x\6+2x - 6\x²-9

Answer 1

1.原式=(3a+2b+a+b-b+a)/5a²b=(5a+2b)/3a²b
2.原式=(m+2n+n+2m)/n-m=3(m+n)/(n-m)
3.原式=(a-3)/(a-3)(a+3)+6/(a-3)(a+3)=(a-3+6)/(a-3)(a+3)=(a+3)/(a-3)(a+3)=1/(a-3)
4.原式=(x+3)/(x+3)(x-3)+(0.5-0.5x)(x-3)/(x+3)(x-3)-6/(x+3)(x-3)=-(x-3)(x-3)/2(x+3)(x-3)=-(x-3)/2(x+3)

Answer 2

（1）（3a+2b+a+b-b-a）/5a²b=(3a+2b)/5a²b
(2) (m+2n-n+2m)/n-m=(3m+n)/n-m
(3) =(a-3)/(a-3)(a+3)+6/(a-3)(a+3)=(a-3+6)/(a-3)(a+3)=1/a-3
(4)=2(x+3)/2(x²-9)+(1-x)(x-3)/2(x²-9)-12/2(x²-9)=[2x+6-x²+4x-3-12]/2(x²-9)=(-x²+6x-9)/2(x²-9)=-(x-3)/2(x+3)