化简 ( 1÷a-b-1÷a+b )÷ab÷a²-b²
化简 (a²+b²/a²-b²-a-b/a+b)÷2ab/(a-b)(a+b)&
化简 b²-a²/a²-ab÷(a+(2ab+b²/a))·(1/a+1/b)
计算:a/b(a-b)-b/a(a-b);(1/a+1/b)÷a²+2ab+b²/a+b.
【4ab/(a-b)+(a/b-b/a)÷(1/a+1/b)】÷(a²+2ab+b²)化简
1-a-b/a+2b÷a²-b²/a²+4ab+4b²
a(a-1)-(a×a-b)=-5,求(a×a+b×b)÷2-ab
计算:[a-b分之4ab+(b分之a-a分之b)÷a分之1+b分之1)]÷(a²+2ab+b²)
化简[(3a-4b)(-3a-4b)-(4b-3a)²-3a(1/3ab²+a-b)]÷(-3a)
3ab+3b²/b(a²+2ab+b²) ×a²-b²/a-b ÷b/
计算 (a²-2ab+b²-a+b)÷(a-b) (a+b)²÷(a-b)
(a+b/a-b)²×2a-2b/3a+3b÷ab/a²-b²
(1)先化简,后求值:(a+b/a-b)²×2a-2b/3a+3b÷ab/a²-b²,其中