$\lim_{x\to\infty}\left(\frac{9x}{9x+2}\right)^{8x}$

$\lim_{x\to-2}\:\:x^2-4$

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

$\frac{d}{dx}\left(\ln\left(x^2+y^4\right)\right)$

$a\left(x+1\right)-x-1$

$2\cdot\sqrt{40}\cdot\sqrt{50}\cdot\sqrt{80}$

$2x\left(1-y\right)+3a\left(1-y\right)$