Combinatorial Enumeration. That whole class was a rollercoaster ride of mind-blowing generating functions to prove crazy things. The exam had ridiculous questions like 'count the number of cactus trees with n vertices such that etc etc etc' and you'd do three pages of terrible terrible sums and algebra. Then your final answer would be something beautiful like n/2 and you'd breath a sigh of relief and thank the math gods.
Put the values of the variables in place of the variables in the expression, then do the arithmetic.

Answer:the third one .38x+2.59
Step-by-step explanation:
No amount of donuts yet so that’s why it’s x and there’s a regular fee of 2.59 so that’s why it’s the answer
Answer:
( D )Each sandwich has 2 pounds of ham.