%
% finding prices of coins

a=[300 150 200];%[$ erou yen]
c=[250 300 175];
d=[120 275 375];

b=[2725.5;3106.3;3199];%sums

A=[a;c;d];%puting the vectors in column

%  300x1+150x2+200x3=2725.5
%  250x1+300x2+175x3=3106.3
%  120x1+275x2+375x3=3199.0

%the solution
[x]=inv(A)*b;%inv(A) inversing matrix

disp(['The price of $ is___' ,num2str(x(1))]);
disp(['The price of euro is____' ,num2str(x(2))]);
disp(['The price of yen is___' ,num2str(x(3))]);

%do
% for checking:
delta=A*x-b;
delta