$n+n+n+n$

$\frac{x^3-6x-10}{x-3}$

$\int\frac{\cos\left(9\sqrt{x}\right)}{\sqrt{x}}dx$

$\left(x+y\right)^2dx+\left(x+y\right)^2dy=0$

$tan^2\left(x\right)+sec^2\left(x\right)=sec^4\left(x\right)-tan^4\left(x\right)$

$2x+5\cdot10x+9$

$\lim_{x\to\infty}\left(\sqrt{x+3}-5\right)$