$11xy^2\left(12xy^4\right)$

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

$\left(b-3y\right)\left(b+15y\right)$

$9x^2-21x$

$3x+2<6x-8$

$\left(x^2+4x+4\right)^{\left(x^2+6x+6\right)}^{-6}$

$\frac{dy}{dx}\left(x^2+2y^2=6x-16y+11\right)$