syms A B C D E F G1 G2 G3 G4 H1 H2 H3 I J K L R

% Constants are -> G1 G2 G3 G4 H1 H2 H3
% Output is -> C
% Input(known) is -> R

e1 = B + A == R;
e2 = G1*B - D == 0;
e3 = D - E - F == 0;
e4 = G2*F - I == 0;
e5 = I + L - J == 0;
e6 = G3*J - K == 0;
e7 = H2*K - E == 0;
e8 = G4*K - C == 0;
e9 = H1*C - L == 0;
e10 = H3*C - A == 0;

eqns = [e1 e2 e3 e4 e5 e6 e7 e8 e9 e10];
vars = [A B C D E F I J K L];

[a,b] = equationsToMatrix(eqns,vars);

% This is the matrix:
a

% This is the resultant vector
b

solution = linsolve(a, b);

% This is C
pretty(solution(3))