$$8\cos^2x+14\cos\left(x\right)-9=0$$

$$x^2+3x-72=0$$

$$123+89$$

$$-10+6\left(-5x+3\right)$$

$$\left(-\frac{1}{2}af\right)\cdot\left(12f^3\right)$$

$$\frac{dy}{dx}\left(\frac{-x}{y}\right)$$

$$\frac{dy}{dx}=\frac{12x^2-6xy+y^2}{x^2}$$