Answer
$9$.
Work Step by Step
The given expression is
$=\_p^2+30p+25$
The standard form of the perfect square trinomial is
$=a^2+2ab+b^2$
Write the given expression in standard form.
$=(\_p)^2+2(3p)(5)+5^2$
So the value of $a$ is $3p$.
The missing term is $3^2=9$.
