$$\int_{-4}^4\left(-x\right)dx$$

$$cos^2x=cosx+sen^2x$$

$$\lim_{x\to0}\left(\frac{\left|z\right|}{z}\right)$$

$$4x^2+40x+9$$

$$\lim_{x\to0}\:\left(\:\frac{x^2-4}{2-\sqrt{3x-2}}\right)$$

$$\lim_{x\to\infty}\frac{\left(-8\right)^x}{3^x}$$

$$4x^2+6y=2x-5$$