Solution
= Solution
Combine the exponentials and integrate:
$$
\boxed{\mathcal L[e^{-at}](p)=\int_0^\infty e^{-(p+a)t}\,dt=\frac1{p+a},
\qquad\operatorname{Re}p>-a.}
$$
The parameter $a>0$ makes this convergence half-plane larger than the one for the constant function.