A line passes through two points (a, -2), and (2a-6, 2). Th

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[GMAT math practice question]

A line passes through two points (a, -2), and (2a-6, 2). This line is parallel to the y-axis. What is a?

A. 2
B. 4
C. 6
D. 8
E. 10
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by Max@Math Revolution » Thu Jan 02, 2020 11:25 pm
=>

The x-coordinate of all points on a vertical line must be equal.
Then we have a = 2a - 6 or a = 6.

Therefore, C is the answer.
Answer: C

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by Scott@TargetTestPrep » Wed Jan 08, 2020 7:46 pm
Max@Math Revolution wrote:[GMAT math practice question]

A line passes through two points (a, -2), and (2a-6, 2). This line is parallel to the y-axis. What is a?

A. 2
B. 4
C. 6
D. 8
E. 10
If a line is parallel to the y-axis, it is a vertical line, and so all the x-coordinates of any points on this line are the same. Therefore, we can create the equation to make the two x-coordinates in the given points equal:

a = 2a - 6

-a = -6

a = 6

Answer: C

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