#include <iostream>
using namespace std;
int main()
{
long long int t, a, b, c, d, result;
cin >> t;
for (int i = 0; i < t; i++)
{
cin >> a >> b >> c >> d;
result = (((a % 1000000007) * (b % 1000000007) % 1000000007) - ((c % 1000000007) * (d % 1000000007) % 1000000007) % 1000000007);
cout << result << endl;
}
}
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