A=\(\left(\frac{x+2}{x.\sqrt{x}-1}+\frac{\sqrt{x}}{x+\sqrt{x}+1}+\frac{1}{1-\sqrt{x}}\right)\)\(:\frac{\sqrt{x}-1}{2}\)với x>0, x khác 1
a. Rút gọn A
b. cm 0<A<2
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1: Khi x=9 thì \(A=\dfrac{3+1}{3-1}=\dfrac{4}{2}=2\)
2:
a: \(P=\left(\dfrac{x-2}{\sqrt{x}\left(\sqrt{x}+2\right)}+\dfrac{1}{\sqrt{x}+2}\right)\cdot\dfrac{\sqrt{x}+1}{\sqrt{x}-1}\)
\(=\dfrac{x+\sqrt{x}-2}{\sqrt{x}\left(\sqrt{x}+2\right)}\cdot\dfrac{\sqrt{x}+1}{\sqrt{x}-1}\)
\(=\dfrac{\left(\sqrt{x}+2\right)\left(\sqrt{x}-1\right)}{\left(\sqrt{x}+2\right)\left(\sqrt{x}-1\right)}\cdot\dfrac{\sqrt{x}+1}{\sqrt{x}}=\dfrac{\sqrt{x}+1}{\sqrt{x}}\)
b: \(2P=2\sqrt{x}+5\)
=>\(P=\sqrt{x}+\dfrac{5}{2}\)
=>\(\dfrac{\sqrt{x}+1}{\sqrt{x}}=\sqrt{x}+\dfrac{5}{2}=\dfrac{2\sqrt{x}+5}{2}\)
=>\(\sqrt{x}\left(2\sqrt{x}+5\right)=2\sqrt{x}+2\)
=>\(2x+3\sqrt{x}-2=0\)
=>\(\left(\sqrt{x}+2\right)\left(2\sqrt{x}-1\right)=0\)
=>\(2\sqrt{x}-1=0\)
=>x=1/4
Bạn có thể làm hộ mình câu c được không?Nếu được thì mình cảm ơn bạn nhiều!
Trả lời:
\(P=\left(\frac{x-\sqrt{x}+2}{x-\sqrt{x}-2}-\frac{x}{x-2\sqrt{x}}\right)\div\frac{1-\sqrt{x}}{2-\sqrt{x}}\left(ĐK:x>0,x\ne1,x\ne4\right)\)
\(P=\left[\frac{x-\sqrt{x}+2}{\left(\sqrt{x}-2\right).\left(\sqrt{x}+1\right)}-\frac{x}{\sqrt{x}.\left(\sqrt{x}-2\right)}\right]\div\frac{-\left(\sqrt{x}-1\right)}{-\left(\sqrt{x}-2\right)}\)
\(P=\left[\frac{x-\sqrt{x}+2}{\left(\sqrt{x}-2\right).\left(\sqrt{x}+1\right)}-\frac{\sqrt{x}}{\sqrt{x}-2}\right]\div\frac{\sqrt{x}-1}{\sqrt{x}-2}\)
\(P=\left[\frac{x-\sqrt{x}+2}{\left(\sqrt{x}-2\right).\left(\sqrt{x}+1\right)}-\frac{\sqrt{x}.\left(\sqrt{x}+1\right)}{\left(\sqrt{x}-2\right).\left(\sqrt{x}+1\right)}\right]\times\frac{\sqrt{x}-2}{\sqrt{x}-1}\)
\(P=\left[\frac{x-\sqrt{x}+2-x-\sqrt{x}}{\left(\sqrt{x}-2\right).\left(\sqrt{x}+1\right)}\right]\times\frac{\sqrt{x}-2}{\sqrt{x}-1}\)
\(P=\left[\frac{-2\sqrt{x}+2}{\left(\sqrt{x}-2\right).\left(\sqrt{x}+1\right)}\right]\times\frac{\sqrt{x}-2}{\sqrt{x}-1}\)
\(P=\frac{-2.\left(\sqrt{x}-1\right)}{\left(\sqrt{x}-2\right).\left(\sqrt{x}+1\right)}\times\frac{\sqrt{x}-2}{\sqrt{x}-1}\)
\(P=\frac{-2}{\sqrt{x}+1}\)
Vậy \(P=\frac{-2}{\sqrt{x}+1}\)với \(x>0,x\ne1,x\ne4\)