Answer:
Step-by-step explanation:
I think both are the same because you have equations in the formula and what ever you do on one side you do to the other.
The students that are correct are Jake , and Liu because 51, and 21 are composite.
Hope this helps!
A unit rate simply means how many of one type of units you get per 1 other type of unit.
Examples of that:

This is rate of fluid flow of some pump for example. It pumps 300 liters every second.
Other example:

This is example for speed. Somebody is moving at 50 kilometers per hour (every hour he travels 50 kilometers)
Answer:
D: {-4, -2, 1}
R: {39, 9, -10}
Step-by-step explanation: