Question

三道分式加减题目，跪求，速度！

我要详细过程。不然我看不懂TUT我笨

Answer 1

1、[(x²-2x)/(x²-4)]/[(x-2)-(2x-4)/(x+2)]
=[x(x-2)/(x+2)(x-2)]/[(x²-4-2x+4)/(x+2)]
=[x/(x+2)]*[(x+2)/x(x-2)]
=1/(x-2)
2、[(a-3)/(2a-4)]/[5/(a-2)-(a+2)]
=[(a-3)/2(a-2)]/[(5-a²+4)/(a-2)]
=(a-3)/[2（3-a)(3+a)]
=-1/[2(a+3)]
3、m/(m-n)-n/(m+n)+2mn/(m²-n²)
=(m²+mn-mn+n²)/(m+n)(m-n)+2mn/(m²-n²)
=(m²+n²)/(m²-n²)+2mn/(m²-n²)
=(m²+n²+2mn)/(m²-n²)
=(m+n)²/(m²-n²)