Hi, I'm trying to figure out how to get a pole-zero map from a difference equation. It's for a lecture I've missed but the notes I have skip over them.

I have some difference equations and sketches of solutions but I can't figure out the relationship between them:


Gives a zero at (0,0), and poles at approx (0.2, 0.9) and (0.2, -0.9)


Gives a zero at (0, 0.5) and a pole at (0, -0.3)


Gives a zero at (0, 0) and complex conjugate poles at approximately (-0.4, 0.8) and (-0.4, -0.8)

Any help appreciated, even hints. Thanks