2 The equation of a curve is \(y = x ^ { 2 } - 6 x + k\), where \(k\) is a constant.
- Find the set of values of \(k\) for which the whole of the curve lies above the \(x\)-axis.
- Find the value of \(k\) for which the line \(y + 2 x = 7\) is a tangent to the curve.