$\lim_{x\to0}\left(\frac{sen\left(ax\right)}{tan\left(bx\right)}\right)$

$\lim_{x\to0}\left(\frac{1-\sec\left(x\right)}{\tan\left(x\right)}\right)$

$9y^2+18y+9$

$3x^2+8x+3=0$

$\frac{\left(5y^2-6y+7\right)}{5y-1}$

$\frac{d^2}{dx^2}\left(sin\left(x^2\right)\right)$

$3x-28<8$