Question

How do you complete the square to solve `x^2 – 5x + 8=0`?

Answer 1

Given `x^2-5x+8 = 0`

Completing the square
`x^2-5x+(5/2)^2 + 8 - (5/2)^2 = 0`

`(x-5/2)^2 = 25/4 - 8 = -7/8`

`x-5/2 = +-sqrt(-7/8)`

Note: there are no Real roots

`x = 5/2 +-sqrt(7/8)i`