$15\cdot16$

$\left(x^2-2\right)\left(x^2+2\right)-\left(x^2-2\right)^2$

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

$\int\frac{3x^2-2\sqrt[4]{x}}{x}dx$

$\lim_{x\to0}\left(\frac{sin3x\left(1-cox\left(x\right)\right)}{x^2}\right)$

$\frac{x+1}{x+1}$

$cosh\left(-x\right)=cosh\left(x\right)$