$s^2+18s+81$

$\lim_{x\to\infty}\left(\frac{ln\left(e^{4x}\:+\:3\right)}{\ln\left(e^x+2\right)}\right)$

$\frac{dy}{dx}=-y\cdot tan\left(x\right)+sec\left(x\right)$

$\frac { 4 } { x ^ { 3 } ( x ^ { 2 } + 3 ) }$

$100-\left(-49\right)$

$\frac{dy}{dx}=e^{3x+2}$

$-4y+7y^2+7x-x+3y+x-4y$