A. independent (x) - expenses, dependent (y) - total cost
B. independent (x) - area, dependent (y) - price
C. independent (x) - time, dependent (y) - distance
D. independent (x) - size of carton, dependent (y) - number of items
Answer:
it is not a polynomial it has no degree either .. and we only classify polynomials in accordance with their degrees
Given , revenue function : 
Cost function 
Profit = Revenue - Cost
Hence, P = R(x) - C(x)
Total revenue for x = 12000 is 
Total cost for x = 12000, 
Profit = 60000-28500 = 31500
Answer = 31500
The fromula of a slope:

a) (-1, -8), (-7, -4)
substitute

b) (2.1, 3.8), (3.1, 7.6)
substitute
