SOLUTION: find all the roots: x^3-11x^2-25x-13=0

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Question 636442: find all the roots: x^3-11x^2-25x-13=0
Found 2 solutions by Alan3354, ewatrrr:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
find all the roots: x^3-11x^2-25x-13=0
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If there's an integer root, it's -13 or 13.
Try those first.

Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi,

find all the roots: 

x^3-11x^2-25x-13=0    |Note x = -1 as root:  -1 -11 +25 -13 =  0

(x+1) a factor:

Using synthetic division

-1	1	-11	-25	-13

 	 	-1	 12	 13

 	1	-12	-13	 0

Yields:

  x^2 - 12x - 13 = 0

 (x-13)(x+1) = 0

  x = 13  or  x = -1

x^3-11x^2-25x-13=0 = (x+1)(x+1)(x-13)

Roots are:  -1, -1, 13