Cubic and Quartic Formulae

[LCieParagon]

Quite clearly you can see what I mean when I type: solve(x^3+x+1=0,x)
You receive a decimal value approximately -0.68...

However, there is obviously an exact solution given that it is a cubic polynomial.
You can find this on wolfram alpha at: http://www.wolframalpha.com/input/?i=sol...3D0%2Cx%29

I never understood why calculators with this capability gave approximate answers as opposed to exact.

I mean when computing (-1)^(1/3), you get the principal complex root as opposed to -1. I'm sure the ability is there to put this feature in. Maple does it flawlessly.