Question

1. Find the equation of the line of best fit. (y=mx+b) 2. Use the graph to predict what the correct mileage for a 7-year-old car should be. 3. Using your equation in 7d, calculate the mileage for a 25-year-old car.

Answer 1

From the graph

The two point ( 0, 35.8514 ) and ( 51.269, 0 )

$\begin{gathered} \text{Slope m = }\frac{0\text{ - 35.8514}}{51.269\text{ - 0}} \\ \\ m\text{ = }\frac{-35.8514}{51.269} \\ m\text{ = -0.69928} \\ \\ \text{Intercept b on the y-a}\xi s\text{ = 35.8514} \\ b\text{ = 35.8514} \end{gathered}$

1) y = mx + b

y = -0.69928x + 35.8514

2) Mileage for 7 years

y = -0.69928 ( 7) + 35.8514

y = -4.89496 + 35.8514

y = 30.9564

Mileage for 7 years = 30.9564

3) Mileage for 25 years

y = -0.69928 ( 25) + 35.8514

y = -17.482 + 35.8514

y = 18.3694

Mileage for 25 years = 18.3694