Answers in the attachment
Step by step
1) number of dogs walked 2, 4, 6, 8, 10
Multiply by $4 each dog walked
Less -$20 starting cost
= profit
2) the graph is attached with the (x,y) coordinates for each expression AND the y intercept of (0, -20) which was the start up cost
3) y= 4x - 20
4 is $4 per dog walked
-20 is the start up cost
4) the rate is 4 because $4 per dog walked and x is variable or the amount of dogs walked