$\lim\:_{n\to\:\infty\:}\left(\sqrt{5n^2+4n+2}-\sqrt{5n^2-2n-1}\right)$

$\lim_{x\to0}\:x\:\left(arctg\left(e^x\right)-\frac{\pi}{2}\right)$

$\lim_{x\to0}\frac{x^3-2x^2-71x+72}{x-9}$

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

$4x\left(-m^{14}+3m^5n^2-7m^3n^4\right)$

$\ln\left(x+1\right)=5$

$-\left(-7\right)\cdot\left(-5\right)\cdot\left(-3\right)\cdot\left(-2\right)$