Answer: undefined.
Step-by-step explanation:
Slope of a line having points (a,b) and (c,d) :
[tex]slope =\dfrac{d-b}{c-a}[/tex]
Given : Point of line z = (2,2) and (2,7)
Slope of line z : [tex]\dfrac{7-2}{2-2}=\dfrac{5}{0}=\infty[/tex]
Hence, the slope of line z is undefined.
Since , the slope of two parallel lines are same.
Therefore ,the slope of the line parallel to line z is undefined.