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

$\frac{3\left(a+b\right)^2}{c}\:si\:a=1\:b=3\:c=2$

$\lim_{x\to0}\left(\frac{\ln\left(\sin\left(6x\right)\right)}{\ln\left(\sin\left(x\right)\right)}\right)$

$+\left(-7\right)+2-\left(-3\right)$

$6u+2=9u+14$

$\left(x^6+4\right)\left(x^6-8\right)$

$\frac{1}{x}<2$