Answer:
Answer is option B.
B. (3,-6) and (7,-6)
Step-by-step explanation:
Slope = change in y / change in x
Slope = (y2-y1)/(x2-x1)
For slope to be zero. i.e
0 = (y2-y1)/(x2-x1)
Cross multiple
0*(x2-x1) = (y2-y1)
(y2-y1) = 0.
Implies that slope of a line will be zero when change is y is zero.
So let examine all the line points in our options to determine our answer.
A. (12, 9) and (12,6)
(y2-y1) = 6 - 9 = -3
B. (3,-6) and (7,-6)
(y2-y1) = -6 - (-6) = -6+6 = 0
C. (1,4) and (2,5)
(y2-y1) = 5 - 4 = 1
D. (-9,7) and (9,-7)
(y2-y1) = -7 - 7 = -14
Haven examine our option, we see that our change in y is zero for option B, therefore at point (3,-6) and (7,-6) the slope is zero
