CAS: Roots of a polynomial

Maxima
---------------------------
(%i1) eq1: x^5-x+x*(1-x)^4*(5*a)+x^2*(1-x)^3*(10*b)+
x^3*(1-x)^2*10*(1-b)+x^4*(1-x)*5*(1-a)=0;
(%o1)

(%i2) solve(eq1,x);
(%o2)

(%i3) f1:rhs(%[1] );
(%o3)

(%i4) radcan(f1);
(%o4)

(%i5) ratexpand(%);
(%o5)

(%i6) d1:part(%,1);
(%o6)

(%i7) d2:part(%o5,[2,3,4]);
(%o7)

(%i8) ratsimp(%);
(%o8)

Roots in simplified format is given by

x = 0.5 +/- sqrt((b+1.5a-0.7)/(4b-2a-1.2))


Matlab
-----------------
syms a b x
f = x^5-x+x*(1-x)^4*(5*a)+x^2*(1-x)^3*(10*b)+
x^3*(1-x)^2*10*(1-b)+x^4*(1-x)*5*(1-a);
soln = solve(f,x);
f4 = soln(4,1);
f5 = soln(5,1);

f4 =
1/2/(5*a-10*b+3)*(5*a-10*b+3+(-75*a^2+
100*a*b-10*a+100*b^2-100*b+21)^(1/2))

f5 =
1/2/(5*a-10*b+3)*(5*a-10*b+3-(-75*a^2+
100*a*b-10*a+100*b^2-100*b+21)^(1/2))

It does not simplify roots any further. I tried all sorts of other commands like 'simplify', 'factor' etc. Is it possible to get the simplified form of roots as shown above?

Now scilab comes with its own symbolic toolbox and interface with 'maxima'. Check following link for details.
http://www.cert.fr/dcsd/idco/perso/Magni/s_sym/functions.html