var t,i,j:integer;
    a:array[1..100000,1..100000]of longint;
begin
  readln(t);
  for i:=1 to t do
    for j:=1 to 4 do readln(a[i,j]);
  for i:=1 to t do

    if (a[i,2]-a[i,1]=a[i,4]-a[i,3]) then a[i,5]=(a[i,4])*2-a[i,3]
                                     else a[i,5]=a[i,4]*trunc((a[i,2]/a[i,1]));

  for i:= 1 to t do
    for j:= 1 to 5 do
    writeln(a[i,j]);
end.

哪儿错了？