## What You Need To Know...

Write an equation of a line that models a dataset and use the equation or the graph to make predictions.

- The benchmark will be assessed using MC (Multiple Choice) and FR (Fill in Response) items.
- All items will include data sets.
- Items may require students to describe the slope of the line in terms of the data, recognizing that the slope is the rate of change.
- Items may require students to write an equation of a line that models data and/or use the data to make predictions.
- In items assessing slope as a rate of change, the slope should be presented as a ratio.
- Fill-in response items may require that students provide a slope, the x-coordinate of the x-intercept, the y-coordinate of the y-intercept, or the x-coordinate or y-coordinate of a point of interest.
- Items may be set in either real-world or mathematical contexts.

## Example One

David is training for a marathon. He writes down the time and distance for each training run and then records the data on a scatter plot. He has drawn a line of best fit on the scatter plot, as shown below.

Which statement best expresses the meaning of the slope as a rate of change for this line of best fit?

**A. **It represents the number of miles he will have to run to finish the marathon.

**B. **It represents the average speed, in miles per hour, of his training runs.

**C. **It represents the number of hours he will need to finish the marathon.

**D. **It represents the distances, in miles, that he ran while he was training.

## Example Two

Joel graphed the line shown on the coordinate plane below.

What is the *x*-coordinate of the point at which this line intersects the *x*-axis?

## Example Three

A tank containing water is being drained at a constant rate. The points on the grid below represent the volume of water remaining in the tank as a function of time.

At what rate, in cubic feet per minute, is the volume of the water changing?