Use implicit differentiation where LaTeX:  \displaystyle y is a function of LaTeX:  \displaystyle x to find the derivative of LaTeX:  \displaystyle 2 \sqrt{7} \sqrt{x} \log{\left(y \right)} + 8 \sqrt{7} \sqrt{y} \log{\left(x \right)}=27

Taking the derivative of both sides using implicit differentiation gives: LaTeX:   \frac{2 \sqrt{7} \sqrt{x} y'}{y} + \frac{4 \sqrt{7} y' \log{\left(x \right)}}{\sqrt{y}} + \frac{8 \sqrt{7} \sqrt{y}}{x} + \frac{\sqrt{7} \log{\left(y \right)}}{\sqrt{x}} = 0  Solving for LaTeX:  \displaystyle y' gives LaTeX:  \displaystyle y' = - \frac{8 \sqrt{x} y^{2} + x y^{\frac{3}{2}} \log{\left(y \right)}}{4 x^{\frac{3}{2}} y \log{\left(x \right)} + 2 x^{2} \sqrt{y}}