Bài 8:
a: Ta có: \(\sqrt{4x}=\sqrt{5}\)
\(\Leftrightarrow4x=5\)
hay \(x=\dfrac{5}{4}\)
b: Ta có: \(\sqrt{4\cdot\left(1-x\right)^2}-6=0\)
\(\Leftrightarrow2\left|x-1\right|=6\)
\(\Leftrightarrow\left|x-1\right|=3\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=3\\x-1=-3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=-2\end{matrix}\right.\)
c: Ta có: \(\sqrt{2x-3}=\sqrt{7}\)
\(\Leftrightarrow2x-3=7\)
hay x=5
d: Ta có: \(\sqrt{\left(3x-2\right)^2}=4\)
\(\Leftrightarrow\left|3x-2\right|=4\)
\(\Leftrightarrow\left[{}\begin{matrix}3x-2=4\\3x-2=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}3x=6\\3x=-2\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-\dfrac{2}{3}\end{matrix}\right.\)