Answer:
Part A) see the explanation
Part B)
Step-by-step explanation:
Part A)
we know that
A relationship between two variables, x, and C, represent a proportional variation if it can be expressed in the form or
Let
C ---> is the total cost (represent the output or dependent variable)
x ----> is the number of books (represent the input or independent variable)
In this problem
we have a proportional relationship between the variables x and C
Part B) we know that
The linear equation is given by
The constant of proportionality k is the same that the slope or unit rate of the linear equation
In this problem the constant k is given
so
For x=12 books
substitute in the equation and solve for C
In function notation
