$$\sec\left(x\right)\frac{dy}{dx}=cos\left(\frac{x}{2}\right)$$

$$\frac{-36x^{12}\times\:\:y^9}{-4x^{11}y^8}$$

$$\left(\frac{10x^7y^{-2}+5x^{-5}y+10}{-10x^9y^{-7}}\right)$$

$$x\left(-2\right)\left(-x-4\right)$$

$$121x^2-176x+64=0$$

$$2\left(2\right)\left(1\right)-3\left(2\right)+1^2$$

$$2x^2\:+\:7x\:+\:2$$