I will assume that we are trying to find the slope between (-9,2) and (9, 2)
The slope's equation ⇒
<u>Let's set the variables</u>:
(x1, y1) --> (-9, 2)
(x2, y2) --> (9, 2)
<u>Now let's plug them in:</u>
<u>Thus the slope of the line is 0.</u>
Hope that helps!