Answer:
x = 2 ± [tex]\sqrt{5}[/tex]
Step-by-step explanation:
Given
x² - 4x - 1 = 0 ( add 1 to both sides )
x² - 4x = 1
Using the method of completing the square
Add ( half the coefficient of the x- term )² to both sides
x² + 2(- 2) x + 4 = 1 + 4
(x - 2)² = 5 ( take the square root of both sides )
x - 2 = ± [tex]\sqrt{5}[/tex] ( add 2 to both sides )
x = 2 ± [tex]\sqrt{5}[/tex]
