Question

\(x-3\sqrt{x}-4=0\)

Answer 1

=>x-4 căn x+căn x-4=0

=>căn x-4=0

=>căn x=4

=>x=16

Answer 2

ĐKXĐ: \(x\ge0\)

\(x-3\sqrt{x}-4=0\)

\(\Leftrightarrow x+\sqrt{x}-4\sqrt{x}-4=0\)

\(\Leftrightarrow\sqrt{x}\left(\sqrt{x}+1\right)-4\left(\sqrt{x}+1\right)=0\)

\(\Leftrightarrow\left(\sqrt{x}+1\right)\left(\sqrt{x}-4\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}=-1\left(vn\right)\\\sqrt{x}=4\end{matrix}\right.\)

\(\Rightarrow x=16\)