Answer:
C
Step-by-step explanation:
Given the logarithmic equation

First, notice that

So, there is no possible solutions, all possible solutions will be extraneous.
Solve the equation:

then

Hence,
and
are extraneous solutions
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)

They lie in the same plane is the answer ;)