$\frac{\tan\left(25\right)+\tan\left(110\right)}{1-\tan\left(25\right)\tan\left(110\right)}$

$\int_0^{x+y}sen\left(2x+3y+4z\right)dz$

$5\left(7z+4\right)=-5\left(-5z-4\right)+10$

$\frac{a^{12}}{a^7}$

$\frac{x^4-4}{x^2+2}$

$4x^2-2x-3+6x^2+x-6+2x^2-x+3$

$\left(3x-1\right)\left(4x+6\right)$