The conditions suggested in the question give you
two equations which you can solve to find p¢
and q¢. Use the same formulation to give
(p¢¢,q¢¢).
The problem
'The Matrix' explains how 2 by 2 matrices are used to give
transformations of the plane and how you multiply the position
vector of a point by the matrix to find the image of that point
under the transformation.