Answer
$-1$
Work Step by Step
Using the fact that $\frac{u'}{u}=\ln u $, we have
$$\int_{-e^2}^{-e} \frac{1}{t}dt= \ \ln( |t|)|_{-e^2}^{-e} \\
=\ln e-\ln e^2\\
=\ln e-2\ln e=1-2=-1. $$
where used the properties $\ln e=1$ and $\ln B^x=x\ln B $.