#include <bits/stdc++.h>
using namespace std;
using ll = long long;
struct IoSetup {
  IoSetup() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(10);
    cerr << fixed << setprecision(10);
  }
} iosetup;
template <typename T1, typename T2>
ostream &operator<<(ostream &os, const pair<T1, T2> &p) {
  os << p.first << " " << p.second;
  return os;
}
template <typename T1, typename T2>
istream &operator>>(istream &is, pair<T1, T2> &p) {
  is >> p.first >> p.second;
  return is;
}
template <typename T>
ostream &operator<<(ostream &os, const vector<T> &v) {
  for (int i = 0; i < (int)v.size(); i++) {
    os << v[i] << (i + 1 != (int)v.size() ? " " : "");
  }
  return os;
}
template <typename T>
istream &operator>>(istream &is, vector<T> &v) {
  for (T &in : v) is >> in;
  return is;
}
int main() {
  int t;
  cin >> t;
  while (t--) {
    int n;
    cin >> n;
    vector<int> a(n + 1, 0);
    for (int i = 0; i < n; ++i) {
      cin >> a[i + 1];
    }
    ll sum = accumulate(a.begin(), a.end(), 0ll);
    if (sum % n) {
      cout << -1 << endl;
      continue;
    }
    vector<vector<int>> ans;
    int target = sum / n;
    auto f = [&](int i, int j, int x) {
      a[i] -= x;
      a[j] += x;
      ans.push_back({i, j, x / i});
    };
    for (int i = 2; i <= n; ++i) {
      int rem = (i - (a[i] % i)) % i;
      if (rem) {
        f(1, i, rem);
      }
      f(i, 1, a[i]);
    }
    for (int i = 2; i <= n; ++i) {
      f(1, i, target);
    }
    int m = ans.size();
    cout << m << endl;
    for (int i = 0; i < m; ++i) {
      cout << ans[i] << endl;
    }
  }
}
