Solve the quadratic equation by completing the square. x^2 - 10x + 18 = 0

Okay so basically, you subtract 18 on both sides since the 18 doesn't work, making the equation 
x² - 10x = -18
So then you add (b/2)², which is 25, to both sides, to get 
x² - 10x + 25 = 7
After this, you factor.
(x-5)(x-5) = 7
Then you simplify.
(x-5)² = 7
Then you solve for x.
√(x-5)² = √7
x-5 = (+ or -)√7

~ x= 5 (+ or -)√7 ~

Hope this helps!