Differential Equations

Consider the following differential equation: $t^2 \frac{d^2y}{dt^2} + 7t \frac{dy}{dt} + 8ty = 10 \sin(t)$ Which one of the following options is correct?

Consider the second-order differential equation $\frac{d^2y}{dx^2} + \frac{dy}{dx} + y = 0$ with initial conditions $y(0) = 1$, $\frac{dy}{dx}|_{x=0} = 1$ The solution is given by

Which of the following differential equations is/are nonlinear?