9 The equation of a curve is \(x y = 12\) and the equation of a line \(l\) is \(2 x + y = k\), where \(k\) is a constant.
- In the case where \(k = 11\), find the coordinates of the points of intersection of \(l\) and the curve.
- Find the set of values of \(k\) for which \(l\) does not intersect the curve.
- In the case where \(k = 10\), one of the points of intersection is \(P ( 2,6 )\). Find the angle, in degrees correct to 1 decimal place, between \(l\) and the tangent to the curve at \(P\).