1. Chapter 17 Completing a Square
Common Core Algebra

2. Completing the Square
Video Completing the Square
Kahn Academy Video

3. Completing the Square Write the equation in the form x2 + bx = c
Add to each side of the equation [½(b)]2
Factor the perfect-square trinomial
x2 + bx + [½(b)] 2 = c + [½(b)]2
Take the square root of both sides of the equation
Solve for x

4. Ex: Solve w2 + 6w + 4 = 0 by completing the square
First, rewrite the equation with the constant on one side of the equals and a lead coefficient of 1.
w2 + 6w = – 4
Add [½(b)]2 to both sides:b =  [½(6)]2 = 32 = 9
w2 + 6w + 9 = – 4 + 9
w2 + 6w + 9 = 5
(w + 3)2 = 5
Now take the square root of both sides
See next slide….

5. Now take the square root of both sides…continued from previous slide