Question 95809
Slope represented by m is {{{m=change_in_x/change_in_y}}}
(-2,-6) and (7,-6)

{{{m=(7-(-2))/(-6-(-6))}}}
{{{m=9/0}}}

division by zero is undefined. This would be a horizonal line if plotted. 

That is plainly visible by the same y variables. I went through the slope equation just for demonstration purposes.