Answer:
At 6 p.m., the number of cars in a parking lot is 120
Step-by-step explanation:
At 1 p.m., the number of cars in a parking lot is 78.
Given,

Note that

So, 1 p.m. goes for n = 0, then
6 p.m. goes for n = 5
Thus,

Answer:
x = 7
Step-by-step explanation:
5x-4 = 31
5x = 31+4
5x = 35
x = 7