Question

Rút gọn biểu thức :

N=\(\dfrac{\sqrt{x}+1}{\sqrt{x}-1}-\dfrac{3\sqrt{x}}{x-\sqrt{x}}\) với x>0,x\(\ne\)1

Giải hệ phương trình:

\(\left\{{}\begin{matrix}x+3y=9\\2x-5y=-4\end{matrix}\right.\)

Answer 1

Answer 2

a) Ta có: \(N=\dfrac{\sqrt{x}+1}{\sqrt{x}-1}-\dfrac{3\sqrt{x}}{x-\sqrt{x}}\)

\(=\dfrac{\sqrt{x}+1-3}{\sqrt{x}-1}\)

\(=\dfrac{\sqrt{x}-2}{\sqrt{x}-1}\)

b) Ta có: \(\left\{{}\begin{matrix}x+3y=9\\2x-5y=-4\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}2x+6y=18\\2x-5y=-4\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}11y=22\\x+3y=9\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}y=2\\x=9-3y=9-3\cdot2=3\end{matrix}\right.\)