SOLUTION: Give the x-intercepts, the table of signs and the sketch of the graph. f(x) = x^3 + 2x^2 - 9x - 18

Algebra ->  Graphs -> SOLUTION: Give the x-intercepts, the table of signs and the sketch of the graph. f(x) = x^3 + 2x^2 - 9x - 18      Log On


   

Question 987562: Give the x-intercepts, the table of signs and the sketch of the graph.
f(x) = x^3 + 2x^2 - 9x - 18
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
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The roots of the polynomial  f(x) = x%5E3+%2B+2x%5E2+-+9x+-+18  are  -3,  -2  and  3.  You can check it directly.

So,  the polynomial is factored as  x%5E3+%2B+2x%5E2+-+9x+-+18 = (x+3)*(x+2)*(x-3).  The sketch is shown in the  Figure.



                      Figure

Could you make the table of signs yourself?