$$-7ax\left(-3ab\right)$$

$$3a^2\cdot4a^2$$

$$\left(\frac{3u^2}{4}+\frac{1v^3}{5}\right)$$

$$x^{2\:-\:8x\:+4}$$

$$\left(4x-2\right)\left(3x^2-x+5\right)$$

$$\left(x\cdot y\right)\left(5t+1\right)+\left(x-y\right)$$

$$2\left(2m-1\right)-8m$$