\(\sqrt{3x+1}+1=3x\)
\(\Leftrightarrow\sqrt{3x+1}=3x-1\left(x\ge-\dfrac{1}{3}\right)\)
\(\Leftrightarrow3x+1=\left(3x-1\right)^2\)
\(\Leftrightarrow3x+1=9x^2-6x+1\)
\(\Leftrightarrow9x^2-9x=0\)
\(\Leftrightarrow9x\left(x-1\right)=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=0\left(TM\right)\\x=1\left(TM\right)\end{matrix}\right.\)
KL....