16Hit1600
AlgebraHardLine through two points with the same x

Algebra practice question

The points (2, −3) and (2, 7) both lie on line m in the xy-plane. Which statement about line m is true?

  1. A. Its equation is x = 2, and its slope is undefined.Correct
  2. B. Its slope is 0.
  3. C. Its equation is y = 2.
  4. D. It passes through the origin.

Answer: A. Its equation is x = 2, and its slope is undefined.

Both points have x = 2, so the line is vertical: every point on it has x = 2. A vertical line's slope is undefined (its run is zero).

Why the other answers are wrong

B. Its slope is 0.
A slope of 0 belongs to a horizontal line; this line is vertical.
C. Its equation is y = 2.
y = 2 is horizontal, and neither given point has y = 2.
D. It passes through the origin.
The origin has x = 0, not 2.

More Algebra questions

Not affiliated with the College Board. SAT is a trademark of the College Board.