Answer:
Step-by-step explanation:
5. You are asked to write an equation of the line in slope-intercept form, so you need to determine the slope of the line and the y-intercept.
You're lucky. One of the points, (0,1), has an x-coordinate of 0, so you know that the y-intercept is 1.
Use the coordinates of the points to determine the slope of the line.
slope = (difference in y-coordinates)/(difference in x-coordinates) = (10-1)/(3-0) = 9/3 = 3
The slope-intercept equation of the line is y = 3x+1
:::::
7. When x = 0, function A = 0 and function B = 3, so function B has a greater initial value.
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: 5.6
===================================
Work Shown:
cos(angle) = adjacent/hypotenuse
cos(B) = AB/BC
cos(62) = AB/12
12*cos(62) = AB
AB = 12*cos(62)
AB = 5.63365875
AB = 5.6
Well I would say A because it went from 8 to 38 which is plus ten.