Question

Find the slope of the line through the pair of points.

(-9, -6) and (-9, -8)

Answer 1

it is (y2 - y1)/(x2 - x1)
(-8-(-6))/(-9+9)
which is ∞

ie the line is parallel to the y axis

Answer 2

$\frac{y2-y1}{x2-x1}$

=$\frac{-8+6}{-9+9}$

=$\frac{2}{0}$

=∞(infinite)