This Instructional Activity is a part of the Lesson 2, Unit 6, Grade 8. Linear functions are defined by the equation of a line. The graphs and the equations of the lines are important for understanding the relationship between the two variables represented in the following example x and y. Read through the site's pricing plan. Convey to students that the rate of change and initial value can immediately be found when given an equation written in the form as y = ax +b. Pay careful attention to the interpretation of the rate of change and initial value.