$5\int x^3dx$

$\left(9+3x\right)\left(-3+3x\right)$

$\lim_{x\to\infty}\:sin\left(\frac{\left(x-1\right)}{\left(x+1\right)}\right)$

$\lim_{x\to1}\left(\frac{x^2+x+9}{2x-1}\right)$

$\int x^2\left(x^3-1\right)^2dx$

$\lim_{x\to\infty}\left(x^2-1\right)\cdot e^{-x^2}$

$\lim_{x\to0}\left(\frac{2-\sqrt{x^2-5}}{x\:+3}\right)$