$$\left(30\cdot0\right):\left(\left(-2\right)\cdot3\right)$$

$$\left(a^4x^5+9\right)^2$$

$$\frac{2z+6x}{n}$$

$$\frac{49x^4y^6}{7x^3y^3}$$

$$f\left(x\right)=\frac{11}{4x^3}-\frac{7}{9x}$$

$$\lim_{x\to\infty}\left(\frac{2x^2+3x}{x^2-5}\right)$$

$$4x^2+14x+12$$