$\left(-18\right)^3$

$3^2+\sqrt{100}\:\left(-3\right)^4+\sqrt{49}-\sqrt{1}$

$\lim_{x\to-1}\left(\frac{\sqrt{x}-3}{9-x}\right)$

$3ax^2+6a^2y$

$\lim_{x\to\infty}\left(\frac{\left(10-6x^2\right)}{5+3e^x}\right)$

$tanx\left(1+cos^2x\right)=\frac{1}{\cos xsinx}$

$\frac{-6}{x+5}\ge1$