Answer:
1. D
2. A
Step-by-step explanation:
Q1. Kerry is simplifying 
By the definition of negative powers,

Hence,

So, the first step in simplifying the expression is

Q2. Given the expression

First, use the definition of negative powers:

Thus,

Answer:
V=pi r² h/3
Step-by-step explanation:
V=volume
R=radius
H=height
It would be the girls because 7 divided into 21 equally is 3. So there will be 7 groups of 3 girls.