$4\left(3x\sqrt{5}\right)$

$\frac{\cot^2\left(x\right)+1}{\cot^2\left(x\right)-1}=\sec\left(2x\right)$

$\frac{3}{c^4}+\frac{6a}{c^3}+\frac{3a^2}{c^2}+\frac{a^3}{c}$

$4+3-\left(-6\right)-7$

$\int\sin\frac{x}{y}dx$

$\log\left(x-2\right)=\frac{1}{2}\left(\log\left(18+\log\left(8-2\right)\right)\right)$

$20x^2-9x+1$