\(3x-\sqrt{x}-4=0\)
\(\Leftrightarrow3\left(x-\frac{\sqrt{x}}{3}-\frac{4}{3}\right)=0\)
\(\Leftrightarrow x-2\cdot\sqrt{x}\cdot\frac{1}{6}+\frac{1}{36}-\frac{49}{36}=0\)
\(\Leftrightarrow\left(\sqrt{x}-\frac{1}{6}\right)^2=\left(\frac{\pm7}{6}\right)^2\)
\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x}=\frac{4}{3}\left(c\right)\\\sqrt{x}=-1\left(l\right)\end{matrix}\right.\)
\(\Leftrightarrow x=\frac{16}{9}\)
Ớ :vv có cách khác ez hơn
\(3x-\sqrt{x}-4=0\)
\(\Leftrightarrow3x-4\sqrt{x}+3\sqrt{x}-4=0\)
\(\Leftrightarrow3\sqrt{x}\left(\sqrt{x}+1\right)-4\left(\sqrt{x}+1\right)=0\)
\(\Leftrightarrow\left(\sqrt{x}+1\right)\left(3\sqrt{x}-4\right)=0\)
\(\Leftrightarrow3\sqrt{x}=4\)
\(\Leftrightarrow x=\frac{16}{9}\)
