How to solve for three answers from 3 equations using fsolve

I have three equations:

I've attempted to solve them but i am unsure where i am going wromg

%function file
function n = moles(guess)
    global NC NH NO NCH4 NCO NCO2 NH2 NH2O 
    
    mol1 = guess(1); mol2 = guess(2); mol3 = guess(3);
    
    %equations
    n(1) = NCH4 + NCO + NCO2 - NC;
    n(2) = NCH4 + NH2 + NH2O - NH;
    n(3) = NCO + 2*NCO2 + NH2;

end

%mainfile

%inputs
NC = 10;
NH = 50;
NO = 5 



sol = fsolve('assignment1',guess);

[Torsten]

@Jcy Juice

You need 2 more equations because you have 5 unknown.

Answer 1

[Davide Masiello]

Below, see an example of how to solve the system.

I had to make up the values of the constants since you have not specified them in your question.

clear,clc

% Constants (I made up the values)
molC    = 1;
molH    = 1;
molO    = 1; 
T       = 600;
molCH4  = 1;
molCO   = 1;
molCO2  = 1;
molH2   = 1;
molH2O  = 1;
k1      = 1;
k2      = 1;
P       = 1;
Po      = 1;

% Initial guess
nguess = [2 1 1 3 2];

% Solver
sln = fsolve(@(x)moles(x,molC,molH,molO,T,k1,k2,molCH4,molCO,molCO2,molH2,molH2O,P,Po),nguess)

Equation solved.

fsolve completed because the vector of function values is near zero
as measured by the value of the function tolerance, and
the problem appears regular as measured by the gradient.

sln = 1×5

1.0e-15 * 0.0555 0.0278 0.0278 0.1110 0.0555

% Function
function n = moles(n,molC,molH,molO,T,k1,k2,molCH4,molCO,molCO2,molH2,molH2O,P,Po)
f = [   -n(1) + molCH4 + molCO + molCO2 - molC;...
        -n(2) + 4*molCH4 + 2*molH2 + 2*molH2O - molH;...
        -n(3) + molCO + 2*molCO2 + molH2;...
        -n(4) + 3*log(molH2) + log(molCO) - log(molH2O) - log(molCH4) - log(k1);...
        -n(5) + log(molH2) + log(molCO2) - log(molH2O) - log(molCO) - log(k2)
        ];
end