Work in this section focuses on what it means to be a solution to a linear equation with two variables. First students consider two situations that can naturally be represented by equations of the form . While their contexts differ, the equations that represent each situation are equivalent. Students make sense of what the graph of each equation should look...

In this final section, students have the opportunity to apply their thinking from throughout the unit. As this is a short section followed by an End-of-Unit Assessment, there are no section goals or checkpoint questions.

Work in this section builds on students’ understanding of proportional relationships to introduce linear relationships that are not proportional.

Students begin by determining the height of stacks of cups to make predictions. The relationship in this situation has a constant rate of change, making it linear. But since the graph of the line representing the situation does not go through...

Work in this section takes previous learning with proportional relationships and looks at it from a grade 8 perspective in preparation for work with linear relationships. Students begin the section by observing features of graphs, such as labels and scaling of the axes, to make sense of situations. Students continue to explore the importance of scaling when studying graphs drawn...

Work in this section introduces students to situations that can be represented by lines with a non-positive slope. Students explore a situation where one quantity decreases at a constant rate in relation to a second quantity, and similar situations, in order to compare rates that increase, decrease, or do not change.

Next, students recall earlier work using slope triangles in...