Answer:
C, D, and E
Step-by-step explanation:
When trying to solve for the cost of each item you will find a rainbow fish is $8.50 and a tetra is $2.50. If you use that information to solve the other answer choices C, D, and E would be correct
We have to calculate the difference of the given polynomials, we follows as:

After opening the brackets, the signs of all the terms changes as there is negative sign before the bracket.
=
Combining all the like terms, we get as
=
=
Option A is the correct answer.
We are given that the elevator is descending, so the coefficient of t must be negative. The elevator's initial position is 500 feet above the ground, so this is a positive value of +500. Therefore the only choice that fits these is h(t) = -5t + 500.