Question Number 33860 by anicetoluisjoao@gmail.com last updated on 26/Apr/18
$$\sqrt{\left[{x}+\mathrm{3}{x}\right]×\mathrm{4}}\:\:=\left(\begin{vmatrix}{\mathrm{2}\:\:\:\:\mathrm{4}\:\:\:\mathrm{5}}\\{\mathrm{3}\:\:\:\:\mathrm{5}\:\:\:\:\mathrm{7}}\end{vmatrix}\right) \\ $$