$4x^2-x+2$

$-26+\left(-8-4+2\right)-\left(-5\right)$

$\lim_{x\to\infty}\left(x+\sqrt{x^2-5x}\right)$

$2x^2+10=0$

$tan^2x-6tanx+9$

$\lim_{x\to\infty}\left(\frac{n\cdot\log\left(n^3\right)}{7\cdot n^3\cdot\:\log\:\left(n\right)}\right)$

$\lim_{x\to1}\left(\frac{1-\left|x\right|}{x-1}\right)$