(4a²-20ab+25b²)÷(5b-2a)
化简 (a²+b²/a²-b²-a-b/a+b)÷2ab/(a-b)(a+b)&
3ab+3b²/b(a²+2ab+b²) ×a²-b²/a-b ÷b/
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)
【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
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
计算:a/b(a-b)-b/a(a-b);(1/a+1/b)÷a²+2ab+b²/a+b.
先化简再求值 (a-2b)(a²+2ab+4b²)-a(a-5b)(a+3b),其中a=-1,b=2
已知a²+b²+2a-4b+5=0,则a²-2ab-3b²/a(a-b)+3ab
化简 b²-a²/a²-ab÷(a+(2ab+b²/a))·(1/a+1/b)
先化简,再求值;[(2a-b/a+b)-(b/a-b)]÷{(a-2b/a+b)+[ab/(a-b)²]},其