$$\frac{\frac{a}{b}+2}{a+2b}$$

$$\frac{dy}{dx}=xe^{-ab}-x$$

$$\left(a^{2n}\right)^2$$

$$3x=27$$

$$\frac{1+\sin\left(x\right)}{\cos\left(x\right)+\sin\left(x\right)\cos\left(x\right)}=\frac{1}{\cos\left(x\right)}$$

$$y^2+1y+27$$

$$\:\lim_{x\to\:4}\frac{2-\sqrt{4x-12}}{x-4}\:$$