Chapter 9.2, Problem 56PE

Many statistics courses cover a topic called multiple regression. This provides a means to predict the value of a dependent variable y based on two or more independent variables $x_1,x_2,\mathrm{...},x_n.$ The model $y=a{x}_1+b{x}_2+c$ is a linear model that predicts y based on two independent variables $x_1$ and $x_2$ . While statistical techniques may be used to find the values of a, b, and c based on a large number of data points, we can form a crude model given three data values $\left(x_1,x_2,y\right)$ . Use the information given in Exercises 55-56 to form a system of three equations and three variables to solve for a, b, and c.
The gas mileage y (in mpg) for city driving is given based on the weight of the vehicle $x_1$ (in lb) and on the number of cylinders.

1. Use the data to create a model of the form $y=a{x}_1+b{x}_2+c$ .
2. Use the model from part (a) to predict the gas mileage of a vehicle that is 3800 lb and has 6 cylinders.