a library loans out 3 books every day for a week and no books are returned. the equation below is written to…

a library loans out 3 books every day for a week and no books are returned. the equation below is written to represent the situation: (-3)·7 = -21 which description best explains the meaning of -21 in the equation? a books were loaned out for -21 days. b the library now has -21 books. c the change in the number of books at the library over the course of the week was -21. d the number of books loaned per day was -21.

a library loans out 3 books every day for a week and no books are returned. the equation below is written to represent the situation: (-3)·7 = -21 which description best explains the meaning of -21 in the equation? a books were loaned out for -21 days. b the library now has -21 books. c the change in the number of books at the library over the course of the week was -21. d the number of books loaned per day was -21.

Answer

Answer:

C. The change in the number of books at the library over the course of the week was $- 21$.

Explanation:

Step1: Analyze Option A

The number of days is $7$, not $-21$. So A is wrong.

Step2: Analyze Option B

The number of books can't be negative in this context. So B is wrong.

Step3: Analyze Option C

Since $3$ books are loaned out each day (negative change per day as books are leaving) and for $7$ days, $(-3)\times7=-21$ represents the total change (a decrease of $21$ books) in the number of books at the library over the week. So C is correct.

Step4: Analyze Option D

The number of books loaned per day is $3$, not $-21$. So D is wrong.