Select the correct answer from each drop-down menu. A function is represented by the table
х у
3 2
5 -26
7 -50
The rate of change of the function represented in the table is (blank) for the given x and y-values, the function is (blank)

first blank options:
-13
-12
12
13

second blank options:
increasing
decreasing
constant

Number of books did Gillian buy is 11.

Step-by-step explanation:    

Given : Gillian purchased 25 books at the library book sale. Each hardcover book cost $1.50, and each paperback book cost $0.50. Gillian spent a total of $26.50.

To find : How many paperback books did Gillian buy?

Solution :

The book costs can be represented by the system of equations below.

......(1)

......(2)

Solving the system of equations by substitution method

Substitute h=25-p from (1) into (2)

Substitute back in equation (1),

i.e. there are 11 paperback books and 14 hardcover books.

Therefore, Number of books did Gillian buy is 11.