Question

How do you solve by completing the square `x^2 - 4x - 1 = 0`?

Answer 1

The roots are 2+`sqrt5`; 2-`sqrt5`

Rewrite it as x^2 -4x +4-4-1=0
x^2 -4x+4=5
(x-2)^2 =5
x-2= +`sqrt5`; -`sqrt`5
x= 2 +`sqrt5`; 2-`sqrt5`