Question: how to find the equation of a line with zero slope?
Answer: Horizontal and Vertical Lines and Their Slopes. Recall the slope of a line is a numerical measure of the steepness of the line. We can find a line's slope using the slope formula or the slope-intercept form. • ...  , = 1,3 and. , = 4,3, we get. = − − ...  3 − 3. 4 − 1. = = 0. ...  The slope of any horizontal line is zero, 0.