$$16n^2-72n+81$$

$$\left(x^2+2y-3z\right)^2$$

$$\:6\:\left(x\:+\:4\right)$$

$$\int\frac{1}{\sin\left(2x\right)\cos\left(2x\right)}dx$$

$$\left(\frac{a}{3}-\frac{3}{b}\right)^4$$

$$\left(2x^2-3x+2\right)\left(x+4\right)$$

$$\frac{p^gq^4}{p^3q^{15}}$$