Geometrical effects of conjugation, negation, addition, subtraction, and multiplication by i Q2

In an Argand diagram, the points \(A\), \(B\), \(C\), \(D\) represent the complex numbers \(a\), \(b\), \(c\), \(d\) respectively.

Given that \(ABCD\) is a square described in an anticlockwise sense, with \(a=-4+6\mathbf{i}\) and \(c=12-8\mathbf{i}\), find \(b\) and \(d\).