SOLUTION: Find k if x^3+6x^2+kx+12 is divisible by (x+4)

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Question 1074901: Find k if x^3+6x^2+kx+12 is divisible by (x+4)
Answer by Edwin McCravy(20066)   (Show Source): You can put this solution on YOUR website!

Since x³+6x²+kx+12 is divisible by (x+4),
if we divide by x+4 by synthetic division
we should have a remainder of 0.

To divide by x+4 by synthetic division we 
use the opposite signed version -4

-4|1     6     k      12
  |     -4    -8  -4k+32 
   1     2   k-8  -4k+44

The remainder must = 0

                  -4k+44 = 0
                     -4k = -44
                       k = 11

Edwin
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