solve four variables 1111

A = input('1,2;3,5');

B = input('8,-1;3,7');

C = input('2,6;8,4');

a1=A(1,1);

a2=A(1,2);

a3=A(2,1);

a4=A(2,2);

b1=B(1,1);

b2=B(1,2);

b3=B(2,1);

b4=B(2,2);

c1=C(1,1);

c2=C(1,2);

c3=C(2,1);

c4=C(2,2);

function fun=f(x)

fun(x)=[a1*x(1)+a2*x(3)+x(1)*b1+x(2)*b3-c1;

a1*x(2)+a2*x(4)+x(1)*b2+x(2)*b4-c2;

a3*x(1)+a4*x(3)+x(3)*b1+x(4)*b3-c3;

a3*x(2)+a4*x(4)+x(3)*b2+x(4)*b4-c4];

x=fsolve(f,[0;0]);

end

Answer 1

[Torsten]

function main
  A =  input('1,2;3,5');
  B =  input('8,-1;3,7');
  C =  input('2,6;8,4');
  a1=A(1,1);
  a2=A(1,2);
  a3=A(2,1);
  a4=A(2,2);
  b1=B(1,1);
  b2=B(1,2);
  b3=B(2,1);
  b4=B(2,2);
  c1=C(1,1);
  c2=C(1,2);
  c3=C(2,1);
  c4=C(2,2);
  x=fsolve(@(x)f(x,a1,a2,a3,a4,b1,b2,b3,b4,c1,c2,c3,c4),[0;0;0;0]);
end
function fun = f(x,a1,a2,a3,a4,b1,b2,b3,b4,c1,c2,c3,c4)
  fun=[a1*x(1)+a2*x(3)+x(1)*b1+x(2)*b3-c1;
       a1*x(2)+a2*x(4)+x(1)*b2+x(2)*b4-c2;
       a3*x(1)+a4*x(3)+x(3)*b1+x(4)*b3-c3;
       a3*x(2)+a4*x(4)+x(3)*b2+x(4)*b4-c4];
end

You solve a linear system of equations in x(1) - x(4).

fsolve is designed for nonlinear systems of equations.

Use linsolve instead.

[AAAAA]

It makes sense! thank you very much