since the line is horizontal, the y-value is always the same.
So, the slope,
∆y/∆x = 0/∆x
which is always zero.
slope is rise/run, so if the rise is zero, so is the slope.
explain why the slope of a horizontal line is always zero
2 answers
If a line is horizontal, then all its points are the same distance away, either above or below, from the x-axis, that is,
any two points would have the form (x1,y) and (x2,y)
slope = (y-y)/(x2 - x1) = 0/(x2 - x1) = 0 , assuming x1 ≠ x2
any two points would have the form (x1,y) and (x2,y)
slope = (y-y)/(x2 - x1) = 0/(x2 - x1) = 0 , assuming x1 ≠ x2