Explanation:
the slope of a line is the ratio (y coordinate change / x coordinate change) when going from one point on the line to another.
in other words, it tells us how many units y changes when x changes a certain amount of units.
when going from (2, 0) to (5, 0)
x changes by +3 (from 2 to 5).
y changes by 0 (from 0 to 0).
the slope is 0/3 = 0.
so, for this line y = 0 and never changes.
therefore, it is a horizontal line with the equation
y = 0
which makes it the x-axis itself.