In this lesson, students begin the move from one-variable inequalities to two-variable inequalities. They plot points on a coordinate plane that fit a one-variable inequality to see how that divides the plane. Then, students select points that are on, above, or below a line that represents a given equation. In the associated Algebra 1 lesson, students draw the graph that represents solutions to two-variable inequalities. The work of this lesson supports that learning by providing some additional work that builds on their current understanding of one-variable inequalities and linear equations.
Students look for regularity in repeated reasoning (MP8) when they use the points selected by the class that satisfy a one-variable inequality to determine the region of the plane that represents the solution in two dimensions.
Lesson overview
- 21.1 Warm-up: Describing Regions of the Plane (5 minutes)
- 21.2 Activity: More or Less (20 minutes)
- 21.3 Activity: Above or Below the Line (15 minutes)
Learning goals:
- Draw the solutions to one-variable inequalities on a coordinate plane.
- Write points that are on, above, or below a line represented by a given equation.
Learning goals (student facing):
- Let’s look at inequalities in two dimensions.
Standards:
- This lesson builds towards the standard: CCSS.HSA-REI.D.12MS.A-REI.12MO.A1.REI.C.7MO.A1.REI.C.8
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