function [x]=fgauss(n,Al)
for k=1:(n-1)
[y p]=max(abs(Al(k:n,k))); % calcula as posi�oes dos maiores
elementos e retornam para p
if k>1
p=p+(k-1);
end
Al([p k],:)=Al([k p],:);
for i=k+1:n
m=Al(i,k)./Al(k,k);
Al(i,k)=0;
for j=k+1:n+1
Al(i,j)=Al(i,j)-m*Al(k,j);
end
end
end
A=Al(:,1:n);
b=Al(:,n+1);
x(n)=b(n)/A(n,n);
k=0;
for k=(n-1):-1:1
s=0;
for j=(k+1):n
s=s+A(k,j).*x(j);
x(k)=(b(k)-s)./A(k,k);
end
end
end