$$+2a^2+5a^3-8a+9-6a^3+3a+2+a^2$$

$$\left(6\frac{2}{3}y^2\right)\left(12y\right)$$

$$20x^4-45^3+15x^2-5x$$

$$\lim_{x\to0}\left(\frac{\left(sinx+2\right)^3-8}{tanx}\right)$$

$$30a^5b-60a^3b+30ab$$

$$144a^2+4b^2-48ab$$