solving 5 nonlinear equations and getting error

so i was solving some equations but i keep getting this error

Error using symengine

DOUBLE cannot convert the input expression into a double array.

Error in sym/double (line 613)

Xstr = mupadmex('symobj::double', S.s, 0);

here is the code:

eq1 = (gcr*10^5)/gamma + z(1) - h2...
    - (q3^2 - qt^2)/(2*gravity*A^2) - (0.81*f1*(leqtheo1+sum(l(1:5)))*q1^2)/(gravity*(Di*10^-3)^5);
eq2 = qt - (1+sqrt((leqtheo1+sum(l(1:5)))/(leqtheo2+sum(l))))*q3;
eq3 = v3 - q3/A;
eq4 = re3 - (density*v3*Di*10^-3)/viscosity;
eq5 = f3 - 0.316*re3^-0.25;
x3 = solve(eq1,eq2,eq3,eq4,eq5);
Qtheo(3) = double(x3.qt);
Vtheo(3) = double(x3.v3);
Retheo(3) = double(x3.re3);
Ftheo(3) = double(x3.f3);

[John D'Errico]

That is not the code, since we cannot execute it. there are many, many undefined variables. How can we know what is in them? And since some of them may contain symbolic expressions themselves, we cannot easily help you.

Make it easy to get help, not difficult. Unless, of course, that is your goal.