#include <bits/stdc++.h> using namespace std; int t, n, a[10005], b[10005], c[10005]; double f(double x, int i) { return x * x * a[i] + x * b[i] + c[i]; } double check(double x) { double ans = f(x, 1); for (int i = 2; i <= n; i++) { ans = max(ans, f(x, i)); } return ans; } int main() { cin >> t; while (t--) { cin >> n; for (int i = 1; i <= n; i++) { cin >> a[i] >> b[i] >> c[i]; } double l = 0.00, r = 1000.00, mid1, mid2; while (r - l > 1e-11) { mid1 = l + (r - l) / 3.0; mid2 = r - (r - l) / 3.0; if (check(mid1) > check(mid2)) { l = mid1; } else { r = mid2; } } cout << fixed << setprecision(4) << check(l) << endl; } return 0; }