Question

what is the solution interval of x^3 – 2x^2 – 9x + 18 > 0

Answer 1

would it be c, i graphed it and got these points

Answer 2

i mean b not c

Answer 3

Yes! good job! You can get this answer without graphing by factoring, and that's what you should do for practice:

(x - 2)(x - 3)(x + 3)

and then look for where all factors are positive and where one factor is postivie and the other 2 are negative.

Answer 4

or u mean where two factors are positive and one is negative :)

Answer 5

Basically, the way you do this is by realizing that you have split the number line (x values) into 4 areas and you check the signs for all factors for all 4 areas.

No, I mean where one is positive and 2 are negative.

If you go with 2 positive and one negative, you will get negative values for "y".

Answer 6

ohh is see

Answer 7

Because multiplying 2 negative factors will get you positive. And when you multiply by that third factor which is positive, it is still positive.

Good now. But do practice the factoring and the intervals. It is GREAT practice. It really is.

Answer 8

i will