Question

9. A line has a slope of zero. Which of the

following points could this line pass through?
10.
equat
A. (12, 9) and (12,6)
B. (3,-6) and (7,-6)
C. (1,4) and (2,5)
D. (-9,7) and (9,-7)

Answer 1

Answer is B, -6 - -6 = 0 7-3=4 0/4 =0

A’s slope has no meaning

C’s slope is 1

D’s slope is -14/-18

Answer 2

Answer is option B.

B. (3,-6) and (7,-6)

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