SOLUTION: how do you graph y=3x^3-9x?

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Question 251579: how do you graph y=3x^3-9x?
Answer by oberobic(2304) About Me  (Show Source):
You can put this solution on YOUR website!
With a cubic equation, you have 2 changes of direction in the graph.
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Factoring you find
y=3x%5E3+-+9x
y=3x%28x%5E2-3%29
y=3x%28x-sqrt%283%29%29%28x%2Bsqrt%283%29%29
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So the x-intercepts are 0, and +/-sqrt(3).
The y-intercept occurs when x=0.
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Then build a table of values for x and y to graph it.
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The graph should look like...
%0D%0Agraph%28500%2C500%2C-10%2C10%2C-10%2C10%2C3x%5E3-9%2Ax%29%0D%0A