What is the slope of x=7? Algebra Graphs of Linear Equations and Functions Horizontal and Vertical Line Graphs 1 Answer smendyka Apr 8, 2017 The equation #x = a# where #a# is any number is by definition a vertical line. A vertical line by definition has an undefined slope. Therefore, #x = 7# has an undefined slope. Answer link Related questions What are horizontal or vertical line graphs? What would the #(x,y)# table look like for a horizontal and a vertical line graph? How do you graph #y=4#? What are some examples of when you would see horizontal or vertical line graphs? How do you graph #x=-1#? What is the equation for the x-axis? What is the equation for the y-axis? How do you graph #y=1/2#? How do you graph #x=100#? In which quadrant do the lines #x=3# and #y=-4# intersect? See all questions in Horizontal and Vertical Line Graphs Impact of this question 12246 views around the world You can reuse this answer Creative Commons License