$2xy^2+1-4xy^2+5x+23xy^2-3xy^2$

$\left(2\cdot10^{-6}\right)\cdot\left(6\cdot10^7\right)$

$\lim_{x\to\infty}\left(\sen\left(\frac{\pi}{x^{2}-1}\right)\right)$

$-0,23+1$

$2x^2-x^2+8x$

$x\:+\:2\:\left(-2-x\right)\:-2\:\left(x\:+\:1\right)$

$\lim_{x\to-\infty}\left(\frac{\sqrt{4x^2-3}}{x}\right)$