Use implicit differentiation where LaTeX:  \displaystyle y is a function of LaTeX:  \displaystyle x to find the derivative of LaTeX:  \displaystyle 12 \sqrt{x} \sin{\left(y^{2} \right)} - 7 e^{x} \log{\left(y \right)}=-42

Taking the derivative of both sides using implicit differentiation gives: LaTeX:   24 \sqrt{x} y y' \cos{\left(y^{2} \right)} - 7 e^{x} \log{\left(y \right)} - \frac{7 y' e^{x}}{y} + \frac{6 \sin{\left(y^{2} \right)}}{\sqrt{x}} = 0  Solving for LaTeX:  \displaystyle y' gives LaTeX:  \displaystyle y' = \frac{y \left(- 7 \sqrt{x} e^{x} \log{\left(y \right)} + 6 \sin{\left(y^{2} \right)}\right)}{7 \sqrt{x} e^{x} - 24 x y^{2} \cos{\left(y^{2} \right)}}