One doesn't really need to do substitution, you just need to recognise
\int \frac{f'(x)}{f(x)} \ dx = \ln |f(x)| + c
\int_{-e}^{-2} \frac{1-3x^2}{x-x^3} \ dx = \ln |x - x^3|_{-e}^{-2}
This is a 2U concept
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However if you are intent on using a substituion
u = x-x^3
To get the limit...