I have a transfer function, H(s) = (s-10)/(s+10). I have to graph the bode plot by hand but I was a little confused on how to do this. For the magnitude plot, the poles and zeros cancel so it is just a straight line at 0 dB. What I could not figure out is the Phase angle plot.

When graphing the Phase angle plot by a computer, it looks like the graph has a pole at omega equals 10 and drops down with a slope of -90 degrees. The horizontal asymptotes are at -180 degrees and -360 degrees. To get a graph like this, I think that the transfer function would have to be in the form of something like this: a*/(b*s^2*(s/10+1)^2) where a and b are any positive number.

I can't seem to get this problem in that form... and I'm a little stumped. Does anyone have any ideas or suggestions for this problem? Thanks for any help.