This Problem Set is a part of the Lesson 7, Unit 4, Grade 8. Students know the conditions for which a linear equation has a unique solution, no solution, or infinitely many solutions. The key parts of the discussion are those that point out the characteristics of the constants and coefficients of an equation that allow students to see the structure in equations that lead to a unique solution, no solution, or infinitely many solutions. Go through the discussion with students, or use the activity on page 80 of this lesson.