You surely do not mean " " then? That is a constant. If you mean " " then . But you don't have " in the numerator to use with the "dx".
Instead, write the integral as and do the two integrals separately. If you need to, let u= -x in the first integral and let u= -2x in the second integral.
Possibly a sub of u = e^x was intended. Just in case a picture helps...
... where (key in spoiler) ...
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Don't integrate - balloontegrate!
Balloon Calculus; standard integrals, derivatives and methods
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