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Here’s the unshmoopy question du jour… Which of the following is the graph of y = negative
two-thirds x? Here are the potential answers:
Before we spoil the ending, hit pause and try to solve it yourself.
All right, so we're looking at an equation of a graph.
Do we recognize what form it's in?
Well, slope-intercept form is y = mx + b...and our equation sort of looks like that...
…where m is negative 2/3 and b is 0. Check. Great, so remember what m tells us?
It tells us the slope of the line, or rise over run.
A negative slope tells us that the graph's y values decrease as x increases... so we
know that our answer must either be B or D.
We can rule out graphs A and C because they both have positive slopes.
Concentrating on graphs (B) and (D), a slope of -2 over 3 implies that, from one point
to another, we go down by 2, and to the right by 3.
Both graphs intersect the origin, so if we start from the origin, we would go down 2
units and right 3 units…
…which means we should arrive at the point (3, -2), another point on the line.
Graph D doesn't include (3,-2), so the answer must be B.
There’s always next year, D.