Answer:
Data Set C
Step-by-step explanation:
You can see that the data is best fit and better looking and fitting to the line in the data set C.
Answer:

Step-by-step explanation:
Let
denotes number of pencils, markers, erasers respectively.
For Andrea:

For Justin:

For Virginia:

On subtracting equations (i) and (ii), we get

Put
in equation (i)

Put
in equation (iii)

Multiply equation (iv) by 5 and equation (v) by 6 and then subtract both the equations.

Put
in equation 

Put
in equation (i)

| 2 | I think that’s right
The product is equal zero if one of the factors is equal zero.Therefore: