Rút gọn
\(A=\left(\dfrac{1}{\sqrt{x}-2}+\dfrac{1}{\sqrt{x}+2}\right).\dfrac{x-4}{2\sqrt{x}}\)
\(B=\left(\dfrac{\sqrt{x}}{\sqrt{a}-1}-\dfrac{\sqrt{a}}{\sqrt{a}+1}\right):\dfrac{1}{a-1}\)
\(P=\left(\dfrac{1}{\sqrt{x}-1}-\dfrac{2}{x\sqrt{x}-x+\sqrt{x}-1}\right):\left(1-\dfrac{\sqrt{x}}{x+}\right)\)
Ai giúp tui vs sáng mai nộp rùi!
\(đkx>0;x\ne4\\ A=\left(\dfrac{\sqrt{x}+2+\sqrt{x}-2}{x-4}\right).\dfrac{x-4}{2\sqrt{x}}\\ =\dfrac{2\sqrt{x}}{2\sqrt{x}}=1\\ đka>0;a\ne1\\ B=\left(\dfrac{\sqrt{a}\left(\sqrt{a}+1\right)-\sqrt{a}\left(\sqrt{a}-1\right)}{a-1}\right).\dfrac{a-1}{1}\\ =\dfrac{a+\sqrt{a}-a+\sqrt{a}}{a-1}.\dfrac{a-1}{1}\\ =2\sqrt{a}\\\)
a: \(=\dfrac{\sqrt{x}+2+\sqrt{x}-2}{x-4}\cdot\dfrac{x-4}{\sqrt{x}}=2\)
b: \(=\dfrac{a+\sqrt{a}-a+\sqrt{a}}{a-1}\cdot\dfrac{a-1}{1}=2\sqrt{a}\)
c: \(=\dfrac{x+1-2}{\left(\sqrt{x}-1\right)\left(x+1\right)}\cdot\dfrac{x+1}{x+1-\sqrt{x}}=\dfrac{\sqrt{x}+1}{x-\sqrt{x}+1}\)
