program sum;
{$APPTYPE CONSOLE}
uses SysUtils;
var a : array [0..20] of real;
var i, n : integer;
var x, y : real;
begin
    write('Please Enter n: ');
    readln(n);
    for i := 0 to n do begin
        write('Please Enter a[', i, '] : ');
        readln(a[i]);
    end;
    write('Please Enter x: ');
    readln(x);
    y := a[n];
    i := n - 1;
    while i >= 0 do begin
        y := y * x + a[i];
        i := i - 1;
    end;
    writeln('y =', y:8:3 );
    readln
end.