$\frac{d^{2} y(t)}{d t^{2}}+6 \frac{d y(t)}{d t}+5 y(t)=\frac{d x(t)}{d t}+4 x(t)$ ; for $y(0)=1 ; \quad \frac{d y(t)}{d t}|=-2$ at $t=0$