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

Answer:

Step-by-step explanation:
First, find the <em>rate of</em><em> </em><em>change</em><em> </em>[<em>slope</em>]:

Then plug these coordinates into the Slope-Intercept Formula instead of the <em>Point-Slope</em><em> </em><em>Formula</em><em> </em>since you get it done much swiftly that way. It does not matter which ordered pair you choose:
−4 = ⅓[−12] + b
−4

_______________________________________________
−3 = ⅓[−9] + b
−3

**You see? I told you it did not matter which ordered pair you choose because you will ALWAYS get the exact same result.
I am joyous to assist you anytime.
Let's turn 3 hours and 3 minutes into minutes.
One hour=60×3=180+3=183
So, there's 183 minutes in 3 hours and 3 minutes. We need to divide 26.2 miles by 183.
26.2÷183≈ 0.143
So, Sally ran 0.143 miles every minute.
Answer:
Volume is how much you can put in something like a box. Surface area is how much wrapping paper is needed to cover the box. Words like fill often designated volume while words like cover mean surface area.
Step-by-step explanation:
Volume is how much you can put in something like a box. Surface area is how much wrapping paper is needed to cover the box. Words like fill often designated volume while words like cover mean surface area.