1) Не достаточно информации
2)
Program help1;
Uses Crt;
Var a : Array[1..3, 1..3] of Integer;
i, j, m : Integer;
Begin
ClrScr;
For i := 1 to 3 do
For j := 1 to 3 do
Begin
Write('Введи a[', i, ', ', j, ']: ');
Readln(a[i, j]);
End;
If a[1, 1] > 0 then
m := 4;
If a[1, 1] < 0 then
m := 7;
For i := 1 to 3 do
For j := 1 to 3 do
a[i, j] := a[i, j] * m;
End.
3)
Program help2;
Uses Crt;
Var s : String;
n, i : Byte;
Begin
ClrScr;
Write('Введи строку: ');
Readln(s);
n := 0;
For i := 1 to Length(s) do
if s[i] = '5' then
inc(n);
Write('Цифра 5 встречается ', n, ' раз');
End.