$\frac{\sqrt{x\left(1+5\right)}-3}{x\left(1-4\right)}$

$\frac{1}{y^2}-\frac{\left(-2\right)}{y^4}$

$36y^2+12+1$

$x+y=\frac{a-b}{\sqrt{a}-\sqrt{b}}$

$\lim_{x\to3}\left(\frac{x+7}{\left(x-3\right)^{11}}\right)$

$\frac{dy}{dx}=\frac{2x+1}{x+2}$

$\:\frac{m^4}{121}-\frac{n^6}{169}$