$\frac{\sin\left(w\right)}{\cos\left(w\right)}-\frac{\cos\left(w\right)}{\sin\left(w\right)}$

$\left(12a-7b+4c\right)-\left(-13a-5b+4c\right)$

$\:\frac{2^3-x^3}{2+x}\:$

$6\left(8g+5\right)$

$\lim_{x\to0}\left(\frac{\left\{\frac{1}{\left(2+x\right)}\right\}-\left(\frac{1}{2}\right)}{1}\right)$

$xy+3y\:cuando\:x=\:2,\:\:y=\:4$

$\lim_{x\to3}\left(\frac{\left|x-3\right|}{\left|3-x\right|}\right)$