Answer:
Part A) see the explanation
Part B) see the explanation
Part C) see the explanation
Explanation:
The complete question in the attached figure
Part A) Find and compare the slopes
we have
Function 1

This is a linear equation in slope intercept form

where
y is the price of the building in thousands
x is the floor area in square foot
m is the slope
b is the y-intercept
we have

Function 2
we know that
The formula to calculate the slope between two points is equal to

take two points from the data in the table
(400,32,000) and (700,56,000)
Remember that the price in the table is in thousands
substitute


The slope of the Function 2 is greater than the slope of the Function 1
The slope of the Function 2 is two times the slope of the Function 1
Part B) Find and compare the y-intercept
we know that
The y-intercept is the value of y when the value of x is equal to zero
Function 1

For x=0

Function 2
Find the equation in point slope form

we have

substitute

Convert to slope intercept form
isolate the variable y

For x=0

The y-intercept of the function 1 is $15,000 and the y-intercept of the function 2 is zero (the line passes through the origin)
Part C) Describe each function as proportional or non proportion
we know that
A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form
or
In a proportional relationship the constant of proportionality k is equal to the slope m of the line and the line passes through the origin
so
Function 1
-----> is a non proportional linear function (because the line has a y-intercept)
Function 2
----> is a proportional linear equation (the line passes through the origin)