81.56+n-2.55=0
81.56+n=2.55
n=2.55-81.56
n=-79.01
Answer:

Step-by-step explanation:
Given that x and y are proportional and the equation relating them is
y = rx ← r is the constant of proportionality
To find r use any ordered pair from the table
Using x = 9, y = 4.5 , then
4.5 = 9r ( divide both sides by 9 )
= r , that is
r = 
360÷2/3=
360×3/2 = 1080/2
1080/2 = 540
540 burgers