a) \(\left(2\sqrt{x}-3\right)\left(2+\sqrt{x}\right)+6=0\left(ĐK:x\ge0\right)\)
\(\Leftrightarrow4\sqrt{x}+2x-6-3\sqrt{x}+6=0\)
\(\Leftrightarrow2x+\sqrt{x}=0\)
\(\Leftrightarrow\sqrt{x}\left(2\sqrt{x}+1\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}\sqrt{x}=0\\2\sqrt{x}+1=0\left(loại\right)\end{array}\right.\)\(\Leftrightarrow x=0\)
b)\(\sqrt{x^2-9}-3\sqrt{x-3}=0\left(ĐK:x\ge3\right)\)
\(\Leftrightarrow\sqrt{\left(x-3\right)\left(x+3\right)}-3\sqrt{x-3}=0\)
\(\Leftrightarrow\sqrt{x-3}\left(\sqrt{x+3}-3\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}\sqrt{x-3}=0\\\sqrt{x+3}-3=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=3\left(tm\right)\\x=6\left(tm\right)\end{array}\right.\)
