Finding the integral of exponential function?

Question

$\int{e^{-2x} \sqrt {e^{-2x+1}}dx}$

  I dont know what method or technique should i applied on this one i tried to $let u = \sqrt {e^{-2x+1}} $ but the derivate doesnt cancel the $e^{-2x}$ i even tried to let u the exponent still didnt get it.

Answer 1

hint: $$ \int e^{-2x}\sqrt{e^{-2x+1}}\mathrm dx=\sqrt{e}\int e^{-2x}\sqrt{e^{-2x}}\mathrm dx=\sqrt{e}\int e^{-3x}\mathrm dx $$