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 12717 views around the world You can reuse this answer Creative Commons License