Find two linearly independent solutions of the differential equation

$$\frac{d^{2} y}{d x^{2}}+2 p \frac{d y}{d x}+p^{2} y=0$$

Find also the solution of

$$\frac{d^{2} y}{d x^{2}}+2 p \frac{d y}{d x}+p^{2} y=e^{-p x}$$

that satisfies

$$y=0, \frac{d y}{d x}=0 \quad \text { at } x=0$$