5 x - 8*x
x^5 - 8*x
/ 3/4\ / 3/4\ / 3/4\ / 3/4\ x*\x + 2 /*\x - 2 /*\x + I*2 /*\x - I*2 /
(((x*(x + 2^(3/4)))*(x - 2^(3/4)))*(x + i*2^(3/4)))*(x - i*2^(3/4))
/ 4\ x*\-8 + x /
x*(-8 + x^4)
x^5 - 8.0*x