Question 985475
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3. Find k so that x+9 is a factor if x^3+kx^2+3x-54.

Change sign of +9 in k+9 to -9.  Do synthetic division:

-9 | 1    k       3      -54
   |<u>     -9  -9k+81  81k-756</u>
     1  k-9  -9k+84  81k-810

Set remainder 81k-810 = 0
                  81k = 810
                    k = 10

The others are done the same way.

Edwin</pre>