Интерполяционный многочлен в форме Лагранжа

Program Lagrandzh;
Var M: array [1..2,1..4] of real;
    M1: array [1..1,1..4] of real;
    I,J,N,I1,I2,I3: integer;
    L,X:Real;
Begin
N:=8;
M[1,1]:=-2;
M[1,2]:=0;
M[1,3]:=1;
M[1,4]:=3;
M[2,1]:=72-3*n;
M[2,2]:=N;
M[2,3]:=3*n-39;
M[2,4]:=7*n-93;
Writeln('Введите Х');
Readln(X);
For I:=1 to 2 do
   For J:=1 to 4 do
   Begin
      If I=1 then
       Writeln('Введите X', J-1)
      else
      Writeln('Введите F(X',J-1,')');
      Read(M[I,J]);
   End;
For I:=1 to 2 do
Begin
   For J:=1 to 4 do
   Write(M[I,J]:4:0);
  Writeln;
End;
Writeln;
M1[1,1]:=M[2,1]*(((X-M[1,2])*(X-M[1,3])*(X-M[1,4]))/((M[1,1]-M[1,2])*(M[1,1]-M[1,3])*(M[1,1]-M[1,4])));
M1[1,2]:=M[2,2]*(((X-M[1,1])*(X-M[1,3])*(X-M[1,4]))/((M[1,2]-M[1,1])*(M[1,2]-M[1,3])*(M[1,2]-M[1,4])));
M1[1,3]:=M[2,3]*(((X-M[1,1])*(X-M[1,2])*(X-M[1,4]))/((M[1,3]-M[1,1])*(M[1,3]-M[1,2])*(M[1,3]-M[1,4])));
M1[1,4]:=M[2,4]*(((X-M[1,1])*(X-M[1,2])*(X-M[1,3]))/((M[1,4]-M[1,1])*(M[1,4]-M[1,2])*(M[1,4]-M[1,3])));
L:=M1[1,1]+M1[1,2]+M1[1,3]+M1[1,4];
Writeln(L);
Writeln('..............');
For I:=1 to 4 do
Writeln(M1[1,I]);
Writeln('..............');
For I:=1 to 4 do
Begin
If I=1 then
begin
I1:=2;
I2:=3;
I3:=4;
end
Else If I=2 then
Begin
I1:=1;
I2:=3;
I3:=4;
end
Else If I=3 then
Begin
I1:=1;
I2:=2;
I3:=4;
end
Else If I=4 then
Begin
I1:=1;
I2:=2;
I3:=3;
end;
M1[1,I]:=M[2,I]*(((X-M[1,I1])*(X-M[1,I2])*(X-M[1,I3]))/((M[1,I]-M[1,I1])*(M[1,I]-M[1,I2])*(M[1,I]-M[1,I3])));
End;
L:=M1[1,1]+M1[1,2]+M1[1,3]+M1[1,4];
Writeln(L);
End.