TeX source:

\begin{aligned} \sqrt{2 x+3}+\sqrt{x-2} &=4 \\ \sqrt{2 x+3} &=4-\sqrt{x-2} \\ \sqrt{2(3)+3} &=4-\sqrt{(3)-2} \\ \sqrt{9} &=4-\sqrt{1} \\ 3 &=3 \end{aligned}