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

$$a^4+\frac{p^4}{4}+a^2p^2$$

$$\left(x+3\right)\left(x+2\right)-\left(x+7\right)\left(x-2\right)$$

$$\lim_{x\to-\infty}\left(1-e^{-2x}\right)$$

$$\frac{x^6+3}{x^6}$$

$$4a\left(-2b-6a-4\right)+8a^2$$

$$\lim_{x\to0}\left(\frac{e^x}{8x^5-3x^4}\right)$$