$$2\csc x+1=\csc x+3$$

$$\sqrt{\left(-1\right)^2-4\left(-1\right)+4}$$

$$2x=\frac{3}{x}+\frac{2}{5}$$

$$\int\frac{1}{\sqrt{-4x-9}}dx$$

$$113\:-\:206$$

$$\left(8n-9\right)\left(8n+12\right)$$