$4\cdot3\cdot2\cdot1^4$

$\lim_{x\to0}\left(\frac{\left(13e^{x+1}-13\right)}{ln\left(2x+3\right)}\right)$

$\left(\left(\frac{2}{25}\right)^2\left(\frac{6^3}{2^2}\cdot0.66^{-1}\right)^{-2}\right)^{-1}$

$\left(2m^2+\frac{3}{7}n^2\right)^2$

$\int\sec^6\left(\frac{x}{2}\right)dx$

$-22\pi+50\pi$

$x^4+3x^3-12x^2-13x-15$