How do you solve $a²-a-1=0$ by completing the square?

Question

4922 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-04-15T10:59:55

$a= 1/2+sqrt5/2 or a=1/2-sqrt5/2$

$a^2-a-1=0 or a^2-a-(1/2)^2-5/4=0 or (a-1/2)^2-5/4=0 or (a-1/2)^2=5/4$
$:.a-1/2=sqrt5/2or a-1/2= - sqrt5/2 :. a= 1/2+sqrt5/2 or a=1/2-sqrt5/2$
[Ans]

How do you solve a²-a-1=0a²-a-1=0 by completing the square?