Convert the solution of an ODE to a symfunc (symbolic function)

Question

I am trying to solve y(x) = 20 but y(x) is the result of an ODE.

So, I must do something (obscure and not very well documented?) to convert solution of dsolve to a symbolic function.

It is my first time for symbolics in Octave.

syms y(x);
y(x) = dsolve(diff(y,x) == y(x), y(0) == 10)
solve(y(x) == 20, x)

Answer 1

Ok. After 2 hours of searching, it is

syms y(x);
y(x) = rhs(dsolve(diff(y,x) == y(x), y(0) == 10))
solve(y(x) == 20, x)