$81-9x^2$

$97-31\cdot\:\left(-3\right)$

$\left(-4x^4y\right)\left(-3xy^4\right)$

$\frac{d}{dx}\left(\left(e^{3x^2}\cdot\:\:ln\left(\frac{2}{x-2}\right)\right)\right)$

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

$\left(3x+2\right)\left(1+3x\right)$

$\int\cos^6\left(\frac{x}{2}\right)dx$