Hello! I am doing an optimization and I need to obtain a equilibrium variable that is not the control variable.

I am doing an optimization and I need to obtain a equilibrium variable that is not the control variable. This is my objetive function:

function SA = funsubasta(q,E,D,fc,alpha,rw1,v11,w)
SAA = ((E - D.*q).*q - q.*(fc + (exp(alpha*28/rw1))*v11 + w));
SASA=sum(SAA,2);
SA=-sum(SASA);
end

Each first order conditions equal to w, so w is a equilibrium variable and I need to obtain it. This problem is the same of resolve that de First order Conditions been the same to all the control variables, but I think is more complicated use fsolve because I need that all the FOC been de same.

Please help! Thanks!