$$\frac{\tan\left(3x-3y\right)}{\left(3x-3y\right)}$$

$$\frac{5x^4}{2x^3}$$

$$2n\left(3n^2+5\right)$$

$$\left(\sqrt{y}-4\right)\left(\sqrt{y}+4\right)$$

$$4c^2+13c+3$$

$$\int\frac{\sqrt{x^2-2}}{x}dx$$

$$\left(a^2b^2+81\:c^2\right)\left(a^2b^2-81\:c^2\right)$$