N2013 P1 Q1

Planes \(p\), \(q\) and \(r\) have equations \(x-2z=4\), \(2x-2y+z=6\) and \(5x-4y+\mu z=-9\) respectively, where \(\mu\) is a constant.

1. Given that \(\mu=3\), find the coordinates of the point of intersection of \(p\), \(q\) and \(r\).[2]
2. Given instead that \(\mu=0\), describe the relationship between \(p\), \(q\) and \(r\).[3]