Considering the cubic polynomial

$$y(x)=x^3 + 5x^2 + 8x + 6,$$

show that $x+3$ is a factor of $y(x)$ using the factor theorem.

Sorry, I'm a bit stuck with this question. Would you use long division? Or would that be for the second part of the question where I have to fully factorise $y(x)$ and hence show that $x=−3$ is the only real zero of $y(x)$.?