$\frac{7.5\cdot10^{12}}{2.5\cdot10^4}$

$\frac{4x-2}{7x+1}\ge\:2$

$\frac{dy}{dx}=\frac{y+3}{1-y}$

$x^4+6x^2+1$

$\frac{3}{2}x\frac{1}{3}\:+\frac{5}{2}x\frac{2}{3}$

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

$\left(x^2-3x+9\right)\left(x^2+3x+9\right)$