Respuesta :

(-3,2)(1,2)...notice that the y values are the same.....when the y values are the same u have a horizontal line with a 0 slope.

IF the x values would have been the same (instead of the y values), then u would have had a vertical line with an undefined slope.
slope of a line through two points m=[tex] \frac{y2-y1}{x2-x1} = \frac{2-2}{1-(-3)} = \frac{0}{4} =0[/tex]