Answer:
The equation to represent the amount earned, y, for x number of walks.

The graph of the function is attached below.
Explanation:
- Let 'y' be the amount earned
- Let 'x' be the number of walks
We know that the slope-intercept form of the line equation is

where m is the slope and b is the y-intercept
Given that Finn suggests that club members walk dogs for a fee. Thus, the y-intercept is 0. i.e. b = 0
Given that he proposes they offer 5 walks for $20 and 10 walks for $40 per dog.
Thus, the rate of change of function or slope = (40-20) / (10 - 5)
= 20 / 5
= 4 dollars per walk
so, rate of change = slope = m = 4
Now substitutng m = 4 and b = 0 in the slope-intercept form of the line equation



Therefore, the equation to represent the amount earned, y, for x number of walks.

The graph of the function is attached below.