$P\left(x\right)$ is a second degree polynomial with $P\left(1\right)=0$ and $P\left(-2\right)=0$. Find two first degree factors of $P\left(x\right)$.

Write the polynomial $p\left(x\right)=x^2-4$ as the product of two first degree polynomials.

If $p\left(x\right)=x^2-7x+13$, what is $p\left(3\right)$?