+5 and -5 because you root 25 which gives you + 5 or - 5
I think that the answer is A.
Permutations are written as nPx where n is the number of total choices possible and x is the number of choices that will be used. This is calculated as nPx = n! / (n-x)!.
Permutations represent the number of ways we can choose x objects from n possibilities where the order of selection matters.
Collect like terms
6.5x-4.5x = 6+10
2x = 6+10
Divide both sides
2x = 16
X= 8
