This video explains how to complete the square of a quadratic equation using geometry as well as algebraic methods.
Source: Holt-McDougall - Algebra 2
Source: Holt-McDougall - Algebra 2
Source: Holt-McDougall - Algebra 2
Source: Holt-McDougall - Algebra 2
Source: Holt-McDougall - Algebra 2
Source: Holt-McDougall - Algebra 2
Source: Holt-McDougall - Algebra 2