$\frac{\left(2x^3-3x^2+5x-4\right)}{x^3-x+1}$

$\frac{cosx}{cosx-cos^2x}$

$\left(\frac{3}{4}y-2x\right)x\left(\frac{3}{4}y+2x\right)$

$25m^4-40m^2+16$

$\left(3s^3t^2-8x^2\right)\left(3s^3t^2+8x^2\right)$

$\left(\frac{2}{7}x^5+1\right)\left(\frac{2}{7}x^5-1\right)$

$\left(2sin\left(x\right)-2cos\left(x\right)\right)\left(2sin\left(x\right)-2cos\left(x\right)\right)$