In this lesson, students apply what they learned about transforming expressions into factored form to make sense of quadratic equations and persevere in solving them (MP1). They see that rearranging equations so that one side of the equal sign is zero, rewriting the expression in factored form, and then using the zero product property make it possible to solve equations that they previously could only solve by graphing. Students also use the structure of the factored form to see the number of solutions that the equations have (MP7).