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

$$4x^2-12x-17=0$$

$$x-0.20=56$$

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

$$\frac{\cot\theta-1}{\cot\theta+1}$$

$$16x^2+2x+6$$

$$\frac{d}{dx}\frac{x^3-1}{x^2+3x+4}$$