$\int x.e^{-\left(x-a\right)}dx$

$e^{4lnx}$

$\left(7x^5\right)^2\left(2y^6\right)^5$

$\left(12mn-15a+74bx\right)\left(90a-17mn+2bx\right)$

$\lim_{x\to-\infty}\left(\frac{e^{-x}}{\sqrt{x}}\right)$

$\int5x\left(\sqrt{x}+6\right)dx$

$\int\frac{x}{\left(4x^2-25\right)^3}dx$