$\frac{x^2+13x+42}{x+7}$

$25x^7-10x^5+15x^2-5x^2$

$\frac{1+\cos\left(x\right)}{\sin\left(x\right)}+\frac{\sin\left(x\right)}{1+\cos\left(x\right)}\frac{2}{\sin\left(x\right)}$

$x^2+2y^2=13k^2$

$2\cdot\sqrt[4]{144}+\sqrt{12}$

$e^{\left(2x\right)}-\frac{1}{x}$

$\lim_{x\to0}-6\tan\pi$