Question 848809
When you perform the synthetic division, remember the coefficients of x^3 and x.  Both are 0.  That will lead to the correct answer.  The final factor has to be = to 0.  It will be a+b+c.<P>
The other way to solve this is:<P>
If x+1 is a factor of the polynomial p(x), x=-1 and p(-1) = 0 according to the remainder theorem.<P>
Set p(-1) = 0.  Then solve for a+b+c<P>
{{{ax^4 + bx^2 + c = 0}}}
<P>{{{ a(-1)^4 + b(-1)^2 + c = 0}}}<P>
a+b+c = 0