Lời giải:
ĐKXĐ: \(x\neq \pm 1\)
Gọi biểu thức là $P$. Ta có:
\(P=\frac{(x+1)^2-(x-1)^2}{(x-1)(x+1)}:\left[\frac{2}{(x-1)(x+1)}-\frac{x(x+1)}{(x-1)(x+1)}+\frac{x-1}{(x+1)(x-1)}\right]\)
\(=\frac{x^2+2x+1-(x^2-2x+1)}{(x-1)(x+1)}:\frac{2-x(x+1)+x-1}{(x-1)(x+1)}\)
\(=\frac{4x}{(x-1)(x+1)}:\frac{1-x^2}{x^2-1}=\frac{4x}{x^2-1}:(-1)=\frac{4x}{1-x^2}\)
Rút gọn các biểu thức sau:
\(D=\left(\frac{5\sqrt{x-6}}{x-9}-\frac{2}{\sqrt{x}+3}\right):\left(1+\frac{6}{x-9}\right)\)
\(E=\left(\frac{\sqrt{x}}{3+\sqrt{x}}+\frac{9+x}{9-x}\right).\left(3\sqrt{x}-x\right)\)
Rút gọn biểu thức:
1) \(P=\frac{x^2-\sqrt{x}}{x+\sqrt{x}+1}-\frac{2x+\sqrt{x}}{\sqrt{x}}+\frac{2\cdot\left(x-1\right)}{\sqrt{x}-1}\)
2) \(P=\left(\frac{\sqrt{x}-2}{\sqrt{x}-1}-\frac{\sqrt{x}+2}{x+2\sqrt{x}+1}\right)\cdot\frac{\left(1-x\right)^2}{2}\)
3) \(B=\left(\frac{1-a\sqrt{a}}{1-\sqrt{a}}+\sqrt{a}\right)\cdot\left(\frac{1+a\sqrt{a}}{1+\sqrt{a}}-\sqrt{a}\right)\)
4) \(K=\left(\frac{\sqrt{a}}{\sqrt{a}-1}-\frac{1}{a-\sqrt{a}}\right)\div\left(\frac{1}{\sqrt{a}+1}-\frac{2}{a-1}\right)\)
Rút gọn:
\(A=\left(\frac{2\sqrt{x}}{x\sqrt{x}+x+\sqrt{x}+1}-\frac{1}{\sqrt{x}+1}\right):\left(\frac{2\sqrt{x}}{\sqrt{x}+1}-1\right)\) với \(x\ge0;x\ne1\)
\(B=\left(\frac{\sqrt{x}-1}{\sqrt{x}+1}-\frac{\sqrt{x}+1}{\sqrt{x}-1}\right):\left(\frac{1}{2\sqrt{x}}-\frac{\sqrt{x}}{2}\right)^2\) với \(x>0;x\ne1\)
1/Rút gọn
A=\(\frac{\left(\sqrt{x}+1\right)\left(x-\sqrt{xy}\right)\left(\sqrt{x}+\sqrt{y}\right)}{\left(x-y\right)\left(\sqrt{x^3+x}\right)}\)(x>0; y>0; x#y)
B= \(\left(\frac{1}{\sqrt{x}+1}-\frac{1}{x+\sqrt{x}}\right):\frac{x-\sqrt{x}+1}{x\sqrt{x}+1}\)( x>0)
C=\(\left(\frac{x+1}{\sqrt{x}}+2\right).\frac{\sqrt{x}}{\left(\sqrt{x}+1\right)\left(x\sqrt{x}+1\right)}\)(x>0)
D=\(\left(\frac{x\sqrt{x}-1}{\sqrt{x}-1}+\sqrt{x}\right):\left(x-1\right)-\frac{2}{\sqrt{x}-1}\)(x>=0; x#1)
giúp em với ạ em đang cần gấp ạ
Rút gọn Q = \(\left(1-\frac{\sqrt{x}}{x+1}\right):\left(\frac{1}{\sqrt{x}-1}+\frac{2\sqrt{x}}{x\sqrt{x}+\sqrt{x}-x-1}\right)\)
rút gọn P=\(\left(\frac{\sqrt{x}}{\sqrt{x}-1}+\frac{\sqrt{x}}{x-1}\right).\left(\frac{2}{x}-\frac{2-x}{x\sqrt{x}+x}\right)\)
Rút gọn
A=\(\frac{\left(\sqrt{x}+1\right)^2+\left(\sqrt{x}-1\right)^2}{\left(\sqrt{x}-1\right)\left(\sqrt{x}+1\right)}.\frac{3\sqrt{x}+1}{x-1}\)
Cho biểu thức:
\(\left(\frac{\sqrt{1+x}}{\sqrt{1+x}-\sqrt{1-x}}-\frac{1-x}{\sqrt{1-x^2}-1+x}\right)\left(\sqrt{\frac{1}{x^2}-1}-\frac{1-x}{x}\right).\frac{x}{1-x+\sqrt{1-x^2}}\)
a) Tìm ĐKXĐ
b) Rút gọn bt
Q=\(\left(\frac{\sqrt{x}}{\sqrt{x}-1}+\frac{\sqrt{x}}{x-1}\right):\left(\frac{2}{x}-\frac{2-x}{x\sqrt{x}+x}\right)\left(x\ge0;x\ne1\right)\)
a) Rút gọn Q
b) Tìm x để Q = \(-\frac{1}{2}\)
