Trying to figure out how to find all numbers for which the rational expression is undefined.

Question

9/2z+5

Is the answer -5/2 or -10/9?

I made a mistake in my typing when I asked the question earlier.

Answer 1

9/(2z+5) is undefined when z = -5/2

the way you typed it
9/2z+5 is undefined if z = 0