Answer
$161=R\ne0$
$x+3$ is not factor
Work Step by Step
$f\left( x\right) =-4x^{3}+5x^{2}+8=\left( x+3\right) q\left( x\right) +R$
$\Rightarrow f\left( -3\right) =161=R\ne0$
Since $f\left( -3\right) =R\neq 0$, $x+3$ is not factor
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.