Answer
$p = (x+4)(x+5)$ = $x^2+9x + 20$
Work Step by Step
To find p, we must consider factor the denominator into $(x+4)(x-3)$. For the expression to simplify into $\frac{x+5}{x-3}$, then $(x+4)$ must divide from the numerator and the denominator. We already know $x+5$ is part of the numerator, and now we know that $(x+4)$ is also. So,
$p = (x+4)(x+5)$ = $x^2+9x + 20$
$\frac{x^2+9x+20}{x^2+x-12} = \frac{(x+4)(x+5)}{(x+4)(x-3)} = \frac{x+5}{x-3}$
