$$\lim_{x\to+7}\left(\frac{2-\sqrt{x-3}}{x^2-49}\right)$$

$$xy^{-6}\left(-y^9\right)$$

$$5n+d=365$$

$$27x^3-8b^6$$

$$\left(x+2y\right)\left(x-7y\right)$$

$$\int_1^{\infty}\left(\frac{ln\left(x\right)}{x^{-1}}\right)dx$$