How can I access the numerical vector in a sym variable equation for future use in my program as a numerical value?

>> syms x y
f1=2*(x^2)-(y^2)-9==0;
f1sub=isolate(f1,x);
y0=1;
x1=subs(f1sub,y,y0)
 
x1 =
 
x == (2^(1/2)*10^(1/2))/2

I want to be able to acces the numerical part of a symbolic variable, in this case "(2^(1/2)*10^(1/2))/2" for further use in the program as a numerical variable.

I would appreciate any valuable help with this issue.

Answer 1

[Walter Roberson]

In this situation,

 rhs(x1)

For future use, see also children()