Question

How do you find all the zeros of `F(x)=x^3 + x^2 +9x + 9`?

Answer 1

`-1 and +-3i`,

Explanation:

F( x ) = ( x + 1 ) ( `x^2`+9) = 0
If the sum of the coefficients in F( x ) = 0, ( x`-`1 ) is a factor of F( x ).
If the sum of the coefficients in F(`-` x ) = 0, ( x + 1 ) is a factor.