Unless I'm asleep and don't know it (which certainly could be the case), it's an eyeball problem.
Your told that the transformation is linear, you're given the images of the unit vectors i and j so can you determine a the 2by2 matrix to represent this transformation ? it quiet easy if you are unsure remember that the image of the i vectors tells you that you should easily be able to determine a, b c, and d.
then
Bobak