$\frac{\left(n+4\right)}{\left(n^2+4^n\right)}\:\cdot\:\left(x-3\right)^n$

$x^2-13x+45$

$\frac{dy}{dx}\left(7x^{2\:}=\:5y^2+4xy+1\right)$

$\int\left(-3\left(t+2\right)^{-2}\right)dt$

$\lim_{x\to4}\left(\frac{x^2-x+12}{x^2+x-20}\right)$

$\sqrt{4-2sin^2x}$

$\frac{88y^7}{11y^3}$