$2m\left(-2\right)+n\left(3\right)$

$135\left(z^0\right)$

$5x^2+9=14$

$\left(5x^2\:+\:\frac{3}{5}\right)\left(5x^2-\frac{3}{5}\right)$

$\lim_{x\to\infty}\left(\sqrt{n^2+5n-2}-\sqrt{n^2-3n+2}\right)$

$\frac{1}{\cos\left(a\right)}=\frac{1}{2t^2-1}$

$\int\frac{4}{x^2+9}dx$