#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long int t;
  cin >> t;
  while (t--) {
    long long int a, b, c, d;
    cin >> a >> b >> c >> d;
    if ((b - a) % (c + d) == 0) {
      cout << (b - a) / (c + d) << endl;
    } else {
      cout << "-1" << endl;
    }
  }
}
