是2/a-2/b=1/(a-b)吗?(2b-2a)/ab=1/(a-b),先通分2(b-a)(a-b)=ab-2(a-b)²=ab-2(a²-2ab+b²)=ab2a²+2b²=3ab2(a²+b²)=3aba²+b²=3ab,两边除aba/b+b/a=3/2
