The solution is p = 10 and p = -2
To solve for both p's, you have to find two factors of -20 that when multiplied, equal -20, but when added equal -8 (2 and -10).Since the -20 is negative, one of the numbers has to be negative.
Now that you have the 2 numbers, you solve for "p".
P - 10 = 0. Add 10 to both sides, P = 10
P + 2 = 0. Subtract 2 on both sides. P= -2.
I hope this helps!