$\frac{2tan\left(x\right)}{1+tan^2\left(x\right)}=sen\left(x\right)^2$

$\left(2x+2\right)\left(x^2+3\right)$

$x^2+24x=12$

$\int\frac{4x}{4x\left(x+4x\right)}dx$

$\int\frac{125+55x+4x^2}{\left(x-5\right)\left(x+5\right)^2}dx$

$\left(2x-5\right)\left(2x^2-10x+7\right)^3$

$\frac{x^5-4x^3+x-1}{x^2+1}$