Answer:
2.5x + 20 = y
Explanation:
first, assign a variable to each unknown:
since we don't know how many videos were rented, that can be x, and we don't know the person's total cost, which can be y
x = number of videos rented
y = total cost
so there's always a $20 that's added on as a membership fee, which means that theres going to be a + 20 somewhere.
So, the equation is 2.5x + 20 = y