Question

giúp mình với ạ

 

Answer 1

\(\sqrt{x^2-4}-x+2=0\) (ĐK: \(\left\{{}\begin{matrix}x\ge2\\x\le-2\end{matrix}\right.\))

\(\Leftrightarrow\sqrt{x^2-4}=x-2\)

\(\Leftrightarrow x^2-4=\left(x-2\right)^2\)

\(\Leftrightarrow x^2-4=x^2-4x+4\)

\(\Leftrightarrow x^2-x^2+4x=4+4\)

\(\Leftrightarrow4x=8\)

\(\Leftrightarrow x=\dfrac{8}{4}\)

\(\Leftrightarrow x=2\left(tm\right)\)