Dr. Loh’s method, which he also shared in detail on his website, uses the idea of the two roots of every quadratic equation to make a simpler way to derive those roots.

Many former algebra students have painful memories of struggling to memorize the quadratic formula. A new way to derive it, overlooked for 4,000 years, is so simple it eliminates the need.

Before students are presented with the quadratic formula, they’re taught a simpler method to solve certain equations. For simplicity, we’ll consider an equation where a = 1. x² – 4x – 5 = 0 ...