$$\left(+18\right)\cdot\left(-55\right)$$

$$xdx+ye^{-x}dy=0$$

$$\left(3a^{2x+1}-3\right)^2$$

$$\csc x=\left(\frac{\sqrt{13}}{2}\right)$$

$$\left(9x^2+5\right)\left(2-8x^2\right)$$

$$1000-16x^2$$

$$\frac{d}{dx}\frac{2}{3}x^2\sqrt{4x}$$