$\frac{125-345x^{15}}{5-7x^5}$

$5n+15=-60$

$\sin\left(2a\right)=2\cdot\sin\left(a\right)\cdot\cos\left(a\right)$

$6\left(3a\right)^5\left(4b^2\right)^1$

$14x^2-33x-5=0$

$\lim_{x\to0}\left(\frac{6}{x\cdot\cot\left(3x\right)}\right)$

$\frac{1}{1-\cos\left(a\right)}+\frac{1}{1+\cos\left(a\right)}$