Answer: The answer is 16 not 1
Do you have a specific question we could solve?
Answer:
Option A. 
Step-by-step explanation:
Let
t ------> the number of additional toppings
c ----> the cost of the pizza in dollars
we know that
The linear equation that represent this situation is

This is the equation of the line in slope intercept form
where
the slope m is equal to

the y-intercept b is equal to
-----> the cost of a pizza without topping
7... if you list the factors of all 3 of this number... you will see 7 is the common factor... because:
7x3=21
7x6=42
7x9= 63
R represents regular and F will represent recycled fibers.
R + F = 27
46.99R + 61.99F = 1433.73
This is how you would set the problem up to begin. Let me know if you need help from here!