We want to find out if (x+6) is a factor of the polynomial
[tex]9x^3+57x^2+21x+24[/tex]In order to find this, we can use the factor theorem.
If we have a polynomial f(x) and want to find if (x-a) is a factor of this polynomial, we plug in x = a into the function and if we get 0, (x-a) is a factor(!)
Now, let's plug in:
x = -6 into the polynomial and see if we get a 0 or not.
Steps shown below:
[tex]\begin{gathered} 9x^3+57x^2+21x+24 \\ 9(-6)^3+57(-6)^2+21(-6)+24 \\ =-1944+2052-126+24 \\ =6 \end{gathered}[/tex]Since it doesn't produce a 0, (x + 6 ) is not a factor of the polynomial given.
