Thread: Shear and transformation matrix

Hello,
I have a couple of questions that I need help in, one involving shear and the other involving finding the transformation matrix...

Attached is the graph.

Question 1) Descrive fully the single transformation which maps triangle U onto triangle X.

Question 2) Find the matrix representing the transformation which maps triangle U onto triangle X

for one, I realized it is a shear, to find the scale factor, I have used the shear formula : distance moved due to shear / distance from invariant line (y axis) giving 4/4 = 1 (the scale factor should be -1, can someone tell me how?)

for two, can anyone give me an effective and accurate method of finding the transformation matrix. (the mark scheme says something about simultaneous equations, but no details....)

Please, if anyone can help me, please do, even if you can only solve one of the questions...

Thanks in advance