$\int \frac{1+e^{7 t}}{e^{t}} d t=-e^{-t}+\frac{e^{6 t}}{6}+C$

$\int \frac{1+e^{7 t}}{e^{t}} d t=-e^{-t}+\frac{e^{6 t}}{6}+C$ .