$x^2sin\left(x^2\right)-x^4$

$\frac{x^2-14x+50}{x^2-8}$

$\lim_{x\to\infty}\left(\frac{x\cdot sen\left(x\right)+2}{x^2sen\left(x\right)+x}\right)$

$5x+6=21$

$\left(6mn^43m^5p\right)^2$

$sin^2\frac{2\pi}{5}-cos^2\frac{2\pi\:}{5}$

$\left(9ab^4+c^5\right)\left(9ab^8-c^5\right)$