#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <cmath>
#include <cstring>
#include <unordered_map>
#include <unordered_set>

#pragma GCC optimize(2)
#pragma GCC optimize(3)
#define IOS std::ios::sync_with_stdio(false)
#define inf 0x3f3f3f3f
#define YES cout << "YES" << endl;
#define yes cout << "yes" << endl;
#define no cout << "no" << endl;
#define NO cout << "NO" << endl;
#define int long long
#define x first
#define y second
#define cmp [&](PII a, PII b){ return a.y < b.y; }

const int N = 5e5+10, mod = 1e9+7, M = 1e6+5, K = 1e5+10, Z = 2e5+7;

using namespace std;
typedef long long LL;
typedef priority_queue<int> PQI; 
typedef priority_queue <int, vector<int>, greater<>> PQGI;
typedef pair<int, int> PII;

void solve()
{
    int x, y, a, b; cin >> x >> y >> a >> b;
    int v = a + b, s = y - x;

    if(s % v == 0) cout << s / v << endl;
    else cout << -1 << endl;
    return;
}

signed main()
{
    IOS; cin.tie(nullptr), cout.tie(nullptr); 
    int T = 1;
    cin >> T;
    while( T -- ) solve();
    return 0;
}