9-5 Completing the Square – We reviewed that Completing the square is a method that is used for converting a quadratic expression of the form ax2 + bx + c to the vertex form a(x - h)2 + k. The most common application of completing the square is in solving a quadratic equation. This can be done by rearranging the expression obtained after completing the square: a(x + m)2 + n, such that the left side is a perfect square trinomial. Completing the square method is useful in:
• Converting a quadratic expression into vertex form.
• Analyzing at which point the quadratic expression has minimum/maximum value.
• Graphing a quadratic function.
• Solving a quadratic equation.
• Deriving the quadratic formula.