Education Technology

Middle Grades Math: What's in a Line?

by Texas Instruments


  • Students will interpret the equation y = mx + b as defining a linear function, whose graph is a straight line.
  • Students will be able to recognize equations as defining linear functions from those that are not linear.
  • Students will reason abstractly and quantitatively.
  • Students will look closely to discern a pattern or structure.


  • equation
  • tables
  • graph
  • coordinates
  • function
  • linear function
  • slope or rate of change

About the Lesson

This lesson involves identifying linear functions.
As a result, students will:

  • Plot points on the coordinate graph as they begin to determine features of a linear function.
  • Plot new points for a visual check of the points "working" with the original plotted points.
  • Examine and compare the final equations that appear for each example.
  • See that equations in the form of y = mx + b represent linear functions and that other types of equations produce other functions or possibly non-functions.