Special integral, Help me solve it please!

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  1. When solving a problem i met an integral that: $$\int_0^\infty ln(x)x^ae^{-x}dx$$ Where a is a complex number with a negative real part. Any ideas for solving it?
  2. And other one is: $$\int_0^\infty x^ae^{-x}dx$$ I tried to use gamma function to solve it, however the result is $\Gamma(a)$ and a, as I mentioned is a complex number with neagative real part so any ideas to expansion it? I need some approximation for it or some series then I can try to cut that off.