\(\sqrt{\left(2x-1\right)^2}=3=\sqrt{9}\)

\(\Leftrightarrow\left(2x-1\right)^2=9\Leftrightarrow\left(2x-1\right)^2-3^2=0\)

\(\Leftrightarrow\left(2x-1-3\right)\left(2x-1+3\right)=0\)

\(\Leftrightarrow\left(2x-4\right)\left(2x+2\right)=0\Leftrightarrow4\left(x-2\right)\left(x+1\right)=0\)

=>\(x-1=0\Leftrightarrow x=1\)

=>\(x+1=0\Leftrightarrow x=-1\)

Vậy S = {-1;1}

buồn thì vui lên cho đỡ buồn

thật là hay