A school student did a project on solar energy for a competition. For demo, the lights are set up along a straight line and have charging points at \(C(4, 3)\), \(D(7, 7)\) and \(E(x, y)\). Also, the distance between \(C(4, 3)\) and \(D(7, 7)\) is \(E(x, y)\). Also, the distance between \(C\) and \(E\) is \(10\) units.
1. The distance \(CD\) is
2. The distance \(DE\) is
3. The value of \(x + y\) is