a: Ta có: \(\sqrt{9x-54}-\sqrt{4x-24}=2\)
\(\Leftrightarrow3\sqrt{x-6}-2\sqrt{x-6}=2\)
\(\Leftrightarrow x-6=4\)
hay x=10
b: Ta có: \(\sqrt{4x^2+4x+1}=7\)
\(\Leftrightarrow\left|2x+1\right|=7\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+1=7\\2x+1=-7\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x=6\\2x=-8\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-4\end{matrix}\right.\)
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