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In this lesson, we learn that all quadratic equations can be solved by a method known as completing the square. This method involves changing the left side of the quadratic into a perfect square, which means that we can then take the square root of both sides to find the solutions.
All quadratics can be solved this way, even if they aren't factorable. The famous quadratic formula is actually derived and comes from the method of completing the square, which is something we will discuss in a future lesson.