Question 191251
Find the number of times r is a root of P(x)=0.
P(x)= x^4+4x^3-16x-16; r=-2 
i found the depressed eruation twice but the 
numbers were all messed up. please help and 
explain.
<pre><font size = 4 color = "indigo"><b>
You have to insert a place holder {{{" "+0x^2}}}
and start with

{{{P(x)= x^4+4x^3+0x^2-16x-16}}}

-2 | 1  4  0 -16 -16
   |   -2 -4   8  16
    ----------------
     1  2 -4  -8   0

-2 | 1  2 -4  -8
   |   -2  0   8 
    ------------
     1  0 -4   0


-2 | 1  0 -4
   |   -2  4 
    --------
     1 -2  0


-2 | 1 -2
   |   -2
    -----
     1 -4

We get a 0 remainder 3 times, but
not the 4th time, so -2 is a root
3 times.

Edwin</pre>