Question 783308
Slope is udefined means it is a vertical line with equation {{{x=a}}}{{{number}}} ({{{y}}} can take any value).
Your equation is {{{highlight (x=5)}}}
The graph (line and point shown) is:
{{{drawing(300,300,-2,8,-8,2,
grid(0), line(5,-8,5,2),
circle(5,-7,0.2)
)}}}