Stage 11 · Quadratic Equations

11.2.5 The Geometric Picture of Completing the Square

11.2 Completing the Square: Reshaping the Equation into a Perfect Square

Point 5 of 5

11.2.5 The Geometric Picture of Completing the Square

Core idea

Picture x²+bx as a big square missing a small corner — add (b/2)² to make it whole, and that's literally where "completing the square" gets its name.

Module goal. Learn to rewrite any quadratic equation as a perfect square so you can take roots, laying the foundation for the quadratic formula.
eastmath.com · 11.2 Completing the Square: Reshaping the Equation into a Perfect Square · 11.2.5 The Geometric Picture of Completing the Square