$\left(-781\right)-\left(+643\right)-\left(-103\right)$

$a^2-ab\:entre\:a$

$fcactor\left(x^3-3x-2\right)$

$\lim_{x\to\infty}\frac{\ln\:\left(1-\frac{3}{x}\right)}{x^{-1}}$

$14x^{10}-21x^8$

$\left(-4x^2-2x^{-1}+4\right)+\left(-8x^2+2x^{-1}-16+4x^{-2}\right)$

$\int\frac{2x^2-3x+5}{\left(x-3\right)\left(x+4\right)\left(x+1\right)}dx$