$$\lim_{x\to\infty}\left(\frac{5-6x}{2x+11}\right)$$

$$72x+36y-27az$$

$$\cos\left(3b\right)\cdot\sec\left(15\right)$$

$$\sqrt{100x^2y^8z^4}$$

$$\left(2x-y\right)\left(-x\right)$$

$$-5x+3\:para\:x=-2$$

$$\int_0^{\infty}\left(\frac{5}{1+16x^2}\right)dx$$