Solve crash

[parisse]

As explained above, the polynomial rooter fails (because the precision is not sufficient to find the eigenvalues of the companion matrix numerically), that's why you get wrong roots with proot/fsolve/cfsolve on the Prime.
For polynomial equations with exact coefficients, realroot (in Xcas) will return isolation intervals (i.e. intervals where there is exactly one root), and you can give a precision parameter to refine the isolation interval. There are 3 real roots, you can check that on the Prime

Code:

ma:=maxnorm(coeff(p))+1; sturmab(p,-ma,ma);

Unfortunately, realroot is yet another command that was disabled on the Prime :-(
On the Prime, you can give an initial guess and the iterative method converges:

Code:

fsolve(48.*x*(1.+x)^60 -(1.+x)^60. +1.=0,x=1);
fsolve(48.*x*(1.+x)^60 -(1.+x)^60. +1.=0,x=-2)