$5-2x\:\:si\:x=2$

$\int\frac{3x}{\left(x+3\right)\left(x+4\right)}dx$

$\frac{d}{dx}\cdot x=y$

$2x^2+x^2-4x-1-10x^4-5x^2+20x$

$\lim_{x\to0}\:\left(\frac{x^6+x}{3\sqrt{x^3+x^6}}\right)$

$\int\left(\frac{x+8}{x^2+3x}\right)dx$

$\lim_{x\to0}\left(\frac{xcos\left(x\right)-sin\left(x\right)}{x}\right)$