completing the square

If the equation is x^2 - 18x + 79 = 0

Completing the Square : move the number 79 on the other side of equal sign and use formula as indicated

x^2 +bx +(b/2)^2 = c + (b/2)^2

x^2 - 18x (-18/2)^2 = -70 + (-18/2)^2

x^2 - 18x + 81 = -79 + 81

x^2 - 18x + 81 = 2

(x - 9) (x - 9) = 2

(x - 9)^2 = 2

Now solve for x by applying square root

√(x-9)^2 = ±√(2)

x-9 = ±√(2)

+9 +9

**x = 9 ± √(2)**

## Comments

^{2 }- 18x + 79 = 0?