$\int9cos\left(4x\right)cos\left(9x\right)dx$

$3x+7^2$

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

$\int\left(\frac{2x-3}{\left(x-3\right)^3}\right)dx$

$\left(\frac{1}{2}x\right)+\left(\frac{2}{3}y\right)^2$

$3a-8b+7c-9a-2b-10c$

$9x^4-31x^3-52x$