8.2 + (–8.2) = 0 what property of math is this

Inverse Property of Addition. Addition Property of 0. Inverse Property of Multiplication. hope that helps love!

2 and 3 are the factors of 72 that are multiples of its prime factor.

Factors of 72:
1 x 72
2 x 36
3 x 24
4 x 18
6 x 12
8 x 9

prime factors are factors of a prime number. A prime number is a number above 1 that is only divisible by 1 and itself. 
among all the factors of 72, 2 and 3 are the ones who fit the definition of a prime factor.