1. The following data represents the distance an object falls after being thrown downward from a very high height. I propose that the equation $d(t) = 5 + 4t + 5t^2$ models this data well. Determine which parts of the equation are incorrect, and fix them.

1. The following table represents data for total cost per item produced for Company A and Company B. One of them represents a linear model, the other a quadratic -- identify which is which, and explain how you determined the result.

Is it a quadratic? Or linear?

What are quadratic models all about?

Limitations of linear models. Why do we like them so much?