<span>The input of days results in the output of total collected books. On day 1, 8 books were collected. Both inputs for days 2 and 3 have the same output of 13, meaning that no books were collected for day 3. After 5 days, 21 books were collected. The most books were collected on day 5.</span>
x = 375 and y = 6300. Option C.
Step-by-step explanation:
From the given data we need to find the value of x and y.
First, we will find out the ratio of area and the force.
= 
So,

or, x =
= 375
Again,

or, y = 420×15 = 6300
Hence,
x = 375 and y = 6300.
Answer:
D. x2 + x - 20.
Step-by-step explanation:
(x – 4)(x + 5).
= x(x + 5) -4(x + 5).
= x2 + 5x – 4x – 20.
= x2 + x - 20.