%BACKWARD Backward substitution for upper triangular systems
%         Written by <YOUR NAME> on <TODAY'S DATE>
function x = forward( A, b )
[m,n] = size(A);
if m~=n,              % check if # rows ~= # columns in A
   error('The input matrix, A, is not a square matrix.'),
end
x(m) = b(m)/A(m,m);
for i = m-1:-1:1,     % i starts at 2, end at 4, w/ steps of 1
   x(i) = (b(i)-A(i,i+1:m)*x(i+1:m)')/A(i,i);
end
x = x';               % convert and display result as column