a) \(\sqrt{4x-1}=5\left(đk:x\ge\dfrac{1}{4}\right)\)
\(\Leftrightarrow4x-1=25\)
\(\Leftrightarrow4x=26\Leftrightarrow x=\dfrac{13}{2}\left(tm\right)\)
b) \(\sqrt{4x^2-12x+9}=11\)
\(\Leftrightarrow\sqrt{\left(2x-3\right)^2}=11\)
\(\Leftrightarrow\left|2x-3\right|=11\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-3=11\\2x-3=-11\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=7\\x=-4\end{matrix}\right.\)
c) \(\sqrt{4x+12}-3\sqrt{\dfrac{x+3}{9}}+\dfrac{3}{5}\sqrt{25x+75}=2\left(đk:x\ge-3\right)\)
\(\Leftrightarrow2\sqrt{x+3}-\sqrt{x+3}+3\sqrt{x+3}=2\)
\(\Leftrightarrow4\sqrt{x+3}=2\Leftrightarrow\sqrt{x+3}=\dfrac{1}{2}\)
\(\Leftrightarrow x+3=\dfrac{1}{4}\Leftrightarrow x=\dfrac{1}{12}\left(tm\right)\)
