In this lesson, Ramon explains quadratic inequalities and their graphical representations. He provides examples to illustrate how to solve these inequalities, including finding values of x that satisfy the conditions of being less than or equal to 25 or greater than 16. He emphasizes the importance of including boundary values when applicable and demonstrates how to plot these inequalities on a graph. Overall, the lesson focuses on understanding quadratic functions and their graphical interpretations in relation to inequalities.