$-86x+43>0$

$\log\:_e\left(\frac{2x-4}{\left(x-4\right)}\right)$

$\lim_{x\to\infty}\left(\frac{1}{\sqrt{x}-19}-\frac{38}{x-361}\right)$

$\left|+5\right|-\left|-9\right|$

$2x^4-x^3+5x^2-9x+3$

$\frac{x^3}{\left(1\:+\:2x\right)^2}$

$2-\left[2-\left(-4\right)-12\::\left(-3\right)\right]-\left(5\cdot3-1\right)$