Question

without graphing, determine whether the following two points would be on a vertical line or a horizontal line.

(3, 4), (3, 8)
vertical
horizontal

Answer 1

8-4/3-3
4/0

The slope is undefined so it's vertical.

Answer 2

Since the x values are identical, the two points have the same x-values, and different y-values. This implies they lie on a vertical line.

Answer 3

(5, 1), (9, 1)

Answer 4

The y-values are identical, so they lie on a horizontal line.

Answer 5

Use the slope formula:

\[m= (y _{2}-y_{1})/(x_{2}-x_{1})\]

y = (8-4)/(3-3) = 5/0 which is undefined so the line is vertical.

Lines with slope m = 0 are horizontal.