For the following differential equations, use MATLAB to find $x(t)$ when $(a)$ all the initial conditions are zero, $(b) x(t)$ when $x(0)=1$ and $\dot{x}(0)=-1$.

(a) $\frac{d^{2} x}{d t^{2}}+10 \frac{d x}{d t}+5 x=11$

(b) $\frac{d^{2} x}{d t^{2}}-7 \frac{d x}{d t}-3 x=5$

(c) $\frac{d^{2} x}{d t^{2}}+3 \frac{d x}{d t}+7 x=-15$(d) $\frac{d^{2} x}{d t^{2}}+7 \frac{d x}{d t}+7 x=26$