39th solve
Q.39. If $\left(ax+b\right)e^{\raisebox{1ex}{$y$}\!\left/ \!\raisebox{-1ex}{$x$}\right.}=x$, then show that $x^3\left(\frac{d^{2}y}{d{x}^2}\right)={\left(x\frac{dy}{dx}-y\right)}^2$