function A=mygaussx(A,r,c)
%以A(r,c)為軸，對列高斯消去
m=min(size(A));                         %取循環次數，行數
A(r,:)=A(r,:)./A(r,c);
for i=1:m
    if i~=r
        A(i,:)=A(i,:)-A(i,c).*A(r,:);
    end
end