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

$$5x+7x-3x+mx+n$$

$$4x^2-12x+4$$

$$\int_{-\frac{\pi}{2}}^{\frac{\pi}{2}}x^2\:cos\left(x\right)dx$$

$$2+x>4$$

$$\left(5x^4+2x^3\right)\left(3x^4\right)$$

$$\left(7x^2+4y^3\right)\left(7x^2+4y^3\right)$$