$\left(+23\right)\:-\:\left(-12\right)\:-\:\left(+7\right)\:+\:\left(-6\right)$

$\lim_{x\to o}\left(\frac{1-cos\left(8x\right)}{1-cos\left(5x\right)}\right)$

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

$\int\left(5-3x\right)dx$

$x\frac{dy}{dx}+3y=\frac{3}{x}-3x$

$\frac{5x^2+20x+16}{x+3}$

$-\left(-8\right)-\left(-20\right)-18$