$\left[\left(-81\right)\cdot\left(-13\right)\right]\cdot\left(-45\right)$

$\lim_{x\to-4}\left(\frac{x^2+7x+3}{x+1}\right)$

$4-\left|8+\left(-11\right)\right|$

$\int\frac{5x^2-36x+48}{\left(x-4\right)^2}dx$

$\int\frac{2u}{4u^2-1}du$

$4x^3-24x^2+36x$

$\lim_{x\to\pi}1+\sin\left(\frac{x}{2}\right)$