## madelyn97 Group Title The function f(x)=x^3-5x^2-2x=24 is positive for what parts of its domain? one year ago one year ago

1. Freyes Group Title

Well in this situation the best thing to do would be to simplify it.. into factors. then you have ranges of test cases to test whether a number is positive in that range

2. Freyes Group Title

can you factor it?

yep! thanks!

4. satellite73 Group Title

is it $f(x)=x^3-5x^2-2x+24$

yeah!

6. satellite73 Group Title

did you factor? once you have the three zeros, because this is a third degree polynomial with positive leading coefficient you know it will be negative, then positive, then negative, then positive

7. satellite73 Group Title

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but that doesnt work right?

10. Freyes Group Title

hmm i can factor this one out give me a second

11. Freyes Group Title

I think what you meant to do was $(x+2)(x-3)(x-4)$

12. Freyes Group Title

This gives you the ranges of $(-\infty, -2) : (-2,3) : (3,4) :( 4,\infty)$

13. Freyes Group Title

Then you can just plug a number from each of those ranges in between and just look at the sign.

14. Freyes Group Title

That'll tell you if it's in the positive range or not

15. cinar Group Title

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