Question

căn x^2-16 - 3 căn x-4

giải pt nha

 

Answer 1

\(=\sqrt{x-4}\left(\sqrt{x+4}-3\right)\)

Answer 2

ĐKXĐ: \(x\ge4\)

\(\sqrt{x^2-16}-3\sqrt{x-4}=0\\ \Leftrightarrow\sqrt{\left(x-4\right)\left(x+4\right)}-3\sqrt{x-4}=0\\ \Leftrightarrow\sqrt{x-4}\left(\sqrt{x+4}-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}\sqrt{x-4}=0\\\sqrt{x+4}=3\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x-4=0\\x+4=9\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=4\left(tm\right)\\x=5\left(tm\right)\end{matrix}\right.\)