$\int\frac{9}{x^2-7x}dx$

$\left(3-4+5-2\right)+\left(3-5-3+2\right)$

$\lim_{x\to-\infty}\left(\frac{\sqrt{7+4x^2}}{2x+5}\right)$

$\lim_{x\to\infty}\left(\frac{3x^3-3x^5+x-2}{1+2x^3-4x^6}\right)$

$3n-12n^2-27-24-9n-30-33-69$

$\left(9a^3\:+\:6c^2\right)^2$

$\lim_{x\to0}\left(\frac{x^4-9sin2x\:}{4x^3}-\frac{9}{2x^2}\right)$