The complex number u is given by \(u = \frac{7 + 4i}{3 - 2i}\).

1. Express u in the form \(x + iy\), where x and y are real.
2. Sketch an Argand diagram showing the point representing the complex number u. Show on the same diagram the locus of the complex number z such that \(|z - u| = 2\).
3. Find the greatest value of \(\arg z\) for points on this locus.