In this lesson, students revisit some situations that can be modeled with quadratic functions, but now in the form of quadratic equations. Quadratic equations are equations that can be written in the form , where  and  are constants and . Students analyze and interpret given equations, write equations to represent relationships and constraints (MP4), and work to solve these equations.  They have already encountered ways to solve quadratic equations specifically written as a factored form equal to zero, but they see that sometimes solutions cannot be easily or precisely found by graphing or reasoning.