Diana is a piano teacher who charges $45 per hour plus an additional flat fee of $20 for travel. the equation that represents this situation is y = 45x + 20, where x represents the number of lesson hours, and y represents the total cost. another piano teacher, paula, creates a graph to compare the total amount diana charges with the total amount she charges for lessons. paula observes that the graph of her function looks the same as the graph of diana's function except that it is shifted 2 units below it. select the function that represents the total amount paula charges. a. f(x) = 43x + 20 b. f(x) = 45x + 18 c. f(x) = 43x + 18 d. f(x) = 45x + 22