## Calculus (3rd Edition)

(a) it is linear with $P=x^2$ and $Q=1$. (b) it is non linear. (c) it is linear with $P=x^{-5}$ and $Q=x^{-5} e^x$. (d) it is non linear.
Since the general form of the first order linear equation is $$y'+P(x)y=Q(x)$$ Then we have (a) the equation is linear with $P=x^2$ and $Q=1$. (b) the equation is non linear. (c) the equation is linear with $P=x^{-5}$ and $Q=x^{-5} e^x$. (d) the equation is non linear.