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

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Answer 1 · 2015-05-22T14:49:46

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

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

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