TeX source:
\begin{array}{rcl}f'_x(x,y) &=& e^{3xy-23}\cdot 3y+y\cdot\dfrac{1}{2}x^{\frac{1}{2}-1}\\\\&=& 3ye^{3xy-23}+\dfrac{1}{2}yx^{-\frac{1}{2}}\\\\&=& 3ye^{3xy-23}+\dfrac{y}{2\sqrt{x}}\end{array}