function [x,y] = hornenguel(p,x0)
    m = coeff(p)
    a = m(length(m))
    b = a
    for i = length(m)- 1:-1:1
        c = m(i) + x0 * a
        if(i <> 1 ) then
         b = c + x0 * a
        end
        a = c
    end
    x = a
    y = b
endfunction