$8x\:-\left(\:6y\:+\:\left[4x-\left(y+8+2x\right)-\left(-3x+2y\right)\:\right]\right)$

$\lim_{x\to0}\left(\frac{ln\left(x^2+12x\right)}{lnx}\right)$

$4\left(x-2\right)+a\left(x-2\right)$

$\int xsen\left(x\right)e^{-sx}dx$

$\frac{\sin\left(x\right)}{1-\cos\left(x\right)}-\frac{1}{\tan\left(x\right)}=\frac{1}{\sin\left(x\right)}$

$-6x+2x+2x-6+6+2y+2x+2y$

$\left(\frac{-105}{+105}\right)$