ShmoopTube

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And here's a shmoop du jour for you and your brain.

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Which of the following is the graph of y = negative two-thirds x?

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Here are the potential answers...

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Hit pause. Try them yourself.

00:19

So we're looking at an equation of a graph.

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Do we recognize what form it's in?

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Well, slope-intercept form is y = mx + b...and our equation sort of looks like that...

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...where m is negative 2/3 and b is 0. Check. Great, so remember what m tells us?

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It tells us the slope of the line, or rise over run.

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A negative slope tells us that the graph's y values decrease as x increases...

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...so we know that our answer must either be B or D.

00:56

We can rule out graphs A and C because they both have positive slopes.

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Concentrating on graphs (B) and (D), a slope of -2 over 3 implies that, from one point

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to another, we go down by 2, and to the right by 3.

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Both graphs intersect the origin, so if we start from the origin,

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we would go down 2 units and right 3 units...

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...which means we should arrive at the point (3, -2), another point on the line.

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Graph D doesn't include (3,-2), so the answer must be B.

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There's always next year, D.

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