SOLUTION: Alggebraically determine the x-intercepts and y-intercepts and sketch the graph of the polynomial : P(x) = 2x^3 -9x^2 +7x +6 Thank you for any help.

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Question 1181246: Alggebraically determine the x-intercepts and y-intercepts and sketch the graph of the polynomial : P(x) = 2x^3 -9x^2 +7x +6
Thank you for any help.

Found 2 solutions by josgarithmetic, MathLover1:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Rational roots theorem should show zeros to be -1/2, 2, and 3. If let x equal to 0, this should give the y-intercept.

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Possible Roots (zeros) to check according to Rational Root Theorem:
-3,+3,-2,+2,-1,+1,-1/2,+1/2

TEST FOR SOME ROOTS
3   |   2   -9   7   6
    |
    |       6   -9  -6
    ---------------------
        2  -3  -2   0           linear root x-3


2  |   2   -3   -2
   | 
   |       4     2
   ------------------
       2    1    0            linear root x-2

Other linear root according to result in the synthetic division,
2x+1

The function, factorized is highlight%28P%28x%29=%28x-3%29%28x-2%29%282x%2B1%29%29.
The zeros are 3, 2, -1/2.

You can find the y-intercept.

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
P%28x%29+=+2x%5E3+-9x%5E2+%2B7x+%2B6............factor completely, write -9x%5E2 as -3x%5E2-6x%5E2, and 7x as 9x-2x
P%28x%29+=+2x%5E3+-3x%5E2-6x%5E2+%2B9x-2x+%2B6............group

P%28x%29+=+%282x%5E3-6x%5E2%29+-%283x%5E2+-9x%29-%282x-6%29

P%28x%29+=+2x%5E2%28x-3%29+-3x%28x+-3%29-2%28x-3%29

P%28x%29+=+%28x+-+3%29+%282x%5E2+-+3x+-+2%29......-3x as -4x%2Bx

P%28x%29+=+%28x+-+3%29+%282x%5E2+-+4x%2Bx+-+2%29.........group

P%28x%29+=+%28x+-+3%29+%28%282x%5E2+-+4x%29%2B%28x+-+2%29%29

P%28x%29+=+%28x+-+3%29+%282x%28x+-+2%29%2B%28x+-+2%29%29

P%28x%29+=+%28x+-+3%29+%28x+-+2%29+%282+x+%2B+1%29

solutions:

+%28x+-+3%29+%28x+-+2%29+%282+x+%2B+1%29=0

if +%28x+-+3%29+=0=>x=3
or
if ++%28x+-+2%29+=0=>x=2
or
if +%282+x+%2B+1%29=0=>x=-1%2F2

so, x-intercepts are at:
(3, 0)
(2, 0)
(-1%2F2, 0)

to find y-intercept, set x=0
P%28x%29+=+%280+-+3%29+%280+-+2%29+%282+%2A0+%2B+1%29
P%28x%29+=+%28-+3%29+%28-+2%29+%28+1%29
P%28x%29+=+6

y-intercept is at:
(0, 6)

+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+2x%5E3+-9x%5E2+%2B7x+%2B6%29+