Step-by-step explanation:
9) C
10) B
11) (b-5)(b+8)
12) (7w - 2)²
13) 14(5x + 2)(3x - 1)
14) (4h - 1) and (h + 6)
15) 3 and (a - 2) and (a + 8)
16) 5 and (4w - 1) and (w + 2)
Answer:
There are 795 combinations.
Step-by-step explanation:
The number of ways or combinations in which we can select k element from a group of n elements is given by:

So, if Miriam want to choose 3 movies with at least two comedies, she have two options: Choose 2 comedies and 1 foreign film or choose 3 comedies.
Then, the number of combinations for every case are:
1. Choose 2 Comedies from the 10 and choose 1 foreign film from 15. This is calculated as:


2. Choose 3 Comedies from the 10. This is calculated as:

Therefore, there are 795 combinations and it is calculated as:
675 + 120 = 795
5x+2y = 20
For every hardcover book (x) you will be charged 5$.
For every paperback book (y) you will be charged 2$.
The amount of both types of books you buy has to be under or equal to 20$