$$\left(6a^3\right)\left(5a^{-9}\right)$$

$$\frac{125y^3+1}{5y+8}$$

$$\left(\frac{2}{5}ab-\frac{1}{2}a^3\right)\left(\frac{2}{5}ab+\frac{1}{2}a^3\right)$$

$$\left(a^2+5\right)\left(a^2-8\right)$$

$$-5\left(8-b\right)$$

$$4\left(2cox\left(x\right)+1\right)=cos\left(x\right)+4$$

$$14m^2m^3+16mn^2-4n^4$$