Question

Rooter Plus charges a $25 service fee plus $40 per hour of work done. Is this a proportional or non-proportional relationship?

Answer 1

Answer:

Non-proportional; the rate of change is $40/hour

Step-by-step explanation:

we know that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form $y/x=k$ or $y=kx$

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

Let

x -----> the number of hours

y ----> The total charge in dollars

The equation of the line in slope intercept form is equal to

$y=mx+b$

where

m is the slope

b is the y-intercept

we have

$m=40\ \ /h\\b=\ 25$

substitute

$y=40x+25$

This relationship is not proportional, because the line not passes through the origin

therefore

Non-proportional; the rate of change is $40/hour