Is there a way to find all roots of a polynomial equation in R?

Is there a way to find all roots of a polynomial equation?

Lets say

x^5+a*x^4+b*x^3+c*x^2+d*x+e=0


how to find its all roots?

polyroot() should be able to do it, assuming that a,b,c,d and e are 
numeric or complex values, not just symbols.

Duncan Murdoch