Complete the square:

2x^2+8x+1

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- Jun 26th 2011, 07:40 AMKhevishcompleting the square
Complete the square:

2x^2+8x+1 - Jun 26th 2011, 08:00 AMskeeterRe: completing the square
- Jun 26th 2011, 08:23 AMKhevishRe: completing the square
how do you get -8? ^^

- Jun 26th 2011, 08:49 AMProve ItRe: completing the square
Maybe it would help if it was written like this

$\displaystyle \displaystyle \begin{align*} 2(x^2 + 4x) + 1 &= 2(x^2 + 4x + 2^2 - 2^2) + 1 \\ &= 2(x^2 + 4x + 4 - 4) + 1 \\ &= 2(x^2 + 4x + 4) + 2(-4) + 1 \\ &= 2(x^2 + 4x + 4) - 8 + 1 \end{align*}$