A=[1,10,100,1000;1,15,225,3375;1,20,400,8000;1,22.5,506.25,11390.625];
b=[227.04;362.78;517.35;602.97];
n=length(b);
for k=1:n-1
  for i=k+1:n
    factor=A(i,k)/A(k,k);
    A(i,k:n)=A(i,k:n)-factor*A(k,k:n);
    b(i)=b(i)-factor*b(k);
  endfor
endfor
A
x=zeros(n,1);
for i=n:-1:1
  x(i)=(b(i)-A(i,i+1:n)*x(i+1:n))/A(i,i);
endfor
y=x(1)+x(2)*16+x(3)*16*16+x(4)*16*16*16;
disp(y)