$$\left(\frac{1}{4}x+\frac{2}{5}y\right)\left(\frac{1}{4}x-\frac{2}{5}y\right)$$

$$+1-\left(-8\right)\cdot\left(+9\right)$$

$$6\:sinx+14cosx$$

$$21+x<25$$

$$\int\left(sin^9\left(2x\right)cos^3\left(2x\right)\right)dx$$

$$\int\left(\frac{x^3}{\left(x^4-6\right)^2}\right)dx$$

$$\frac{dy}{dx}=3x^2+x$$