I need to solve this integral:

$\displaystyle \int_{a,b} \frac{1}{\gamma(\alpha)\beta^\alpha} x^{\alpha-1} e^{-x/\beta} \frac{1}{Z}\frac{p^{\alpha -1}e^{-\beta q}}{{\gamma(\alpha)}^r \beta^{-\alpha s}} d{a,b}$

It has been a long time since I took calculus class in the university. Any assistance will be greatly appreciated!