Which two of the following pairs of coordinates will have a slope that is undefined?

Question

a. (6, -9) and (-6, -9)

b. (-6, 1) and (-6, 17)

c. (6, 1) and (6, 9)

d. (-6, 1) and (6, 1)

choose 2 letter choices

Answer 1

a. (6, -9) and (-6, -9)

b. (-6, 1) and (-6, 17)