метод гаусса

помогите с алгоритмом задачи решения СЛАУ методом гаусса с использованием контрольного столбца. Никак не могу найти ошибку. слишком большая погрешность!
Program GaussLab4;
uses crt;
type
matrix=array[1..10,1..10] of real;
vector=array[1..10] of real;
var n,i,j,l: integer;
t,b: real;
A:matrix;
ks,ts, koren:vector;
i3,j3:byte;
raz: array[1..10] of real;
Begin
write('n=');
readln(n);
for i:=1 to n do
for j:=1 to n do
begin
write('A[',i,',',j,']=');
readln(A[i,j]);
end;
writeln('vvod stolbca b');
for i:=1 to n do
begin
write('A[',i,',',n+1,']=');
readln(A[i,n+1]);
end;
for i:=1 to n do
for j:=1 to n+1 do
ks[i]:=ks[i]+A[i,j];
writeln('kontrol stolbec');

for i:=1 to n do Writeln(ks[i]:12:5);
readln;
for i3:=1 to n do
begin
for j3:=1 to n
do write(A[i3,j3]:8:4,' ');write(' | ');write(A[i3,n+1]:8:4,' ');writeln;
end;

for i:=1 to n do
begin
t:=a[i,j];
for j:=i to n+1 do
a[i,j]:=a[i,j]/t;
ks[i]:=ks[i]/t;
for l:=i+1 to n do
begin
b:=a[l,i];

for j:=i to n+1 do
a[l,j]:=a[l,j]-a[i,j]*b;

ks[i+1]:=ks[i+1]-ks[i]*b;
end;
end;
Begin
for i:=1 to n do
begin
ts[i]:=0;
for j:=1 to n do
ts[i]:=ts[i]+A[i,j];
ts[i]:=ts[i]+A[i,n+1];
end;
Writeln(' preobrazovanie :');writeln;

writeln(' ks: ts: pogreshnost');
for i:=1 to n do Writeln(ks[i]:12:5,' ',ts[i]:12:5,' ',abs(ks[i]-ts[i]):12:12);
readln;
End;
koren[n]:=a[n,n+1];
for i:=n-1 downto 1 do
begin
koren[i]:=a[i,n+1];
for j:=i+1 to n do
koren[i] := koren[i]-a[i,j]* koren[j];
end;
Writeln('OTVET:');
for i:=1 to n do
Writeln(' koren',i,'=', koren[i]);
Readln;
End.

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