Does line L intersect X-axis?

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by kmittal82 » Tue Apr 03, 2012 5:25 am
(1)
Line could be y=0, which has a 0 slope but intersects the x axis at every point (basically, it is the x-axis)

(2)
Line x = 5 would be a straight vertical line at x = 5, so this means the line in the question stem is parallel to this, which means it must intersect the x axis at some point where x is not 5.

So, (B)

Hope its clear

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by Anurag@Gurome » Tue Apr 03, 2012 5:31 am
ashfu2002 wrote:Q) Does the line L intersect x-axis?

(1) The slope of the line is zero.
(2) The line does not intersect line x=5

OA [spoiler](B)[/spoiler]

can anyone explain?
Let us assume that equation of line L is y = mx + b, where m is the slope of line L and b is the y-intercept.

(1) The slope of the line is zero implies m = 0. Then y = b.
If y = 0, then line L lies on x-axis.
If y = 2, then line L is parallel to x-axis.
No definite answer; NOT sufficient.

(2) The line does not intersect line x = 5 implies line L is parallel to line x = 5, which implies line L intersects the x-axis; SUFFICIENT.

The correct answer is B.
Anurag Mairal, Ph.D., MBA
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