Add 2p² to each side of the equation. Then you have
2p² + 16p + 24 = 0 .
Before you roll up your sleeves and start working on it, you can make it
even more convenient if you divide each side by 2 . Then you have:
p² + 8p + 12 = 0 .
Now you have a nice, comfortable, familiar-looking quadratic equation.
You can either factor the left side into (p + 6) (p + 2), or, if you can't find
the factors, you can apply the quadratic formula to it.
That's how to solve it, and find its two solutions.