$\lim_{x\to+\infty}\left(x\left(arctgx\:-\frac{\pi}{\left(2\right)}\right)\right)$

$\left|-7\right|\left|-5\right|$

$\frac{5}{\sqrt{2}}.\frac{\sqrt{9}}{x+8}$

$\int\:\frac{x^3-1}{x\left(2x+1\right)\left(2x-1\right)}dx$

$2\sqrt{2}-3\sqrt{y}$

$9+6y+6y^2$

$4x^2-2x^3y+6xy^2$