Completing the Square to Solve a Quadratic Completing

Completing the Square to Solve a Quadratic

Completing the Square: A new Way to Solve Quadratics We have seen how to solve the equation below by taking the square root: But, this method only works if the equation is identical to the one above (a perfect square trinomial equals a number). It would be useful to learn how to rewrite an equation (like the one below) so it is identical to the one above. Then, you can apply the square root technique.

Completing the Square to Solve a Quadratic + Solve: + Try to make a Square with the tiles Complete the square by adding the unit tiles needed to make a perfect square to both sides. = – Never complete the square by adding additional variables Since there is one x, you can square root to solve – Factor the perfect square trinomial

Perfect Square A polynomial that can be factored into the following form: (x + a) Examples: 2

Completing the Square x 2 + bx + c is a perfect square if: (The value of c will always be positive. ) Ex: Prove the following is a perfect square Half of b=-16 squared is 64=c

Completing the Square Find the c that completes the square: 1. x 2 + 50 x + c 2. x 2 – 22 x + c 3. x 2 + 15 x + c

Factoring a Completed Square If x 2 + bx + c is a perfect square, then it will easily factor to: Ex: Prove the following is a perfect square. Half of b=+8 is +4

Completing the Square to Solve a Quadratic Solve the following equation by completing the square: 2 ( x – # ) =# GOAL Find the “c” that completes the square Isolate the x terms Factor and Simplify Add the “c” to both sides Solve

Completing the Square to Solve a Quadratic Solve the following equation by completing the square: 2 ( x – # ) = # Isolate the GOAL Find the “c” that completes the square x terms Factor and Simplify Add the “c” to both sides Solve