Wrong output while finding the root by Fixed Point Iteration

I have an equation g = @(x)(5-((5/2)*exp(x/2))-((7/2).x^2)-3*x).^1/3 and, according to specs, the equation has 3 roots. I'd like my code produce me both both x and g(x) value in 2 columns because it'd be easier to get those roots. But my code behaves wrong, it gives me the following when I try to run it:

    xc = fpi(g, 0.5, 20)
x0                               g(x0)
  1.0e+188 *

    0.0000   -0.0000
   -0.0000    0.0000
    0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000    0.0000
    0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -0.0000
   -0.0000   -1.4749
   -1.4749      -Inf
      -Inf       NaN
       NaN       NaN
       NaN       NaN
       NaN       NaN

xc =

   NaN

What did I do wrong? How could it be fixed?

%Program 1.2 Fixed-Point Iteration
%Computes approximate solution of g(x)=x
%Input: inline function g, starting guess x0, 
%       number of steps k
%Output: Approximate solution xc
function xc=fpi(g,x0,k)
x(1)=x0;
for i=1:k
  x(i+1)=g(x(i));
end
xc=x(k+1);
disp('x0                               g(x0)');
disp([x', g(x)']);

Answer 1

[Walter Roberson]

g = @(x)(5-((5/2)*exp(x/2))-((7/2).x^2)-3*x).^1/3

is invalid syntax. You need * between the (7/2) and the x^2

With that correction, the equation does not have 3 roots, it has 5 roots, 2 of which are real. They are approximately

-1.5622276995472072141
.42511928810478633643
13.857652165630850665+22.906093584614758165*i
11.453142346661211379+8.8602737198488354732*i
11.453142346661211379-8.8602737198488354732*i