Question

How do you solve `-2x^2 + 5x + 1/8` by completing the square?

Answer 1

Change side and divide by a:

`f(x) = x^2 - 5/2 x - 1/16 = 0`

`f(x) = x^2 - 5/2 x + 25/16 - 25/16 - 1/16 = 0`

`( x - 5/4)^2 = 25/16 + 1/16 = 26/16`

`(x - 5/4) = (sqr26)/4 --> x = 5/4 + (sqr26)/4`

`(x - 5/4) = (-sqr26)/4 --> x = 5/4 - (sqr26)/4`