This answer to the problem is f (x) =-15/2x^2 + 5x +C
-∞ ≤ x ≤ ∞
Because x has no limit so it can be between negative infinity and positive infinity. It's just a symbol that lets you know that x can be any number.
It takes 3 years. If your question has a graph you can solve by looking at the graph but if not then I already answered it and I'm letting you know it should be 3 years.
Answer:

, it's 85
Step-by-step explanation:
for explanation see the attachment.