ex find the equation of a horizontal and vertical line given the graph solution find the slope of vertical and horizontal lines a horizontal line red in the diagram as it moves out of the system to the left or right this is a horizontal asymptote with the equation y 1 image titled find the distance between two points step 2 ex 2 find the equation of a line in standard form given two points horizontal and vertical lines horizontal and vertical tangent lines image titled find the equation of a tangent line step 6 how to find slope of a line given 2 points some key topics that involve finding the equation of a line horizontal line graph equation of horizontal line through one point calculator tessshlo image titled use the slope intercept form in algebra step 1 image titled use distance formula to find the length of a line step 1 image titled find the equation of a tangent line step 1 image titled find the slope of an equation step 4 image titled find the slope of a line step 1 we can see that the x value of the x intercept is a mixed number between 2 and 3 to algebraically find x intercepts recall that we must set y 0 and as an exercise plot the given two points and verify that they lie on a vertical line image titled find the equation of a tangent line step 3 ex determine the points where a function has horizontal tangent lines you what are horizontal lines definition equations lesson transcript study com