Slope

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Slope

by Sak32 » Sun Dec 08, 2013 11:54 am
In the xy plane, is the slope of line k equal to 0?

1) The x-intercept of k is 0.
2) The y-intercept of k is 0.

Please provide clear explanations. Thank you.

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by [email protected] » Sun Dec 08, 2013 10:58 pm
Hi Sak32,

This DS question asks if a line has a slope of 0. This essentially asks "Is the line horizontal?" This is a YES/NO question.

Fact 1: The X-intercept is 0

This means that the line intercepts the X-axis at the origin (0,0). Unfortunately, we don't know anything else about the line. The slope could be positive (answer is NO), negative (answer is NO) or 0 (answer is YES).
Fact 1 is INSUFFICIENT

Fact 2: The Y-intercept is 0

This also means that the line intercepts the origin (0,0). We still don't know if the slope is positive, negative or 0.
Fact 2 is INSUFFICIENT

Combined, we have 2 Facts that tell us the same thing: the line intercepts the origin (0,0), but we don't know about the slope. We could have a NO or a YES answer.
Combined, INSUFFICIENT

Final Answer: E

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