$-\left|-2\right|-\left|8\right|$

$678-430,081$

$x^2-3x-2$

$9+2.5^2$

$\frac{\sen\left(5x\right)+\sen\left(3x\right)}{\cos\left(3x\right)+\cos\left(x\right)}=1$

$4^5.4^2$

$\frac{1}{\left(e^{2x}\right)+1}-e^{-x}\left(\arctan\left(e^x\right)\right)+e^{-x}\left(\arctan\left(e^x\right)\right)$