How do you complete the square of this problem?
$\displaystyle 5-4x-x^2$
Divide the expression by -1 to get a positive coefficient of $\displaystyle x^2$
$\displaystyle -(x^2+4x-5)$
When completing the square divide $\displaystyle b$ by 2:
$\displaystyle (x+2)^2$. However this gives us $\displaystyle x^2+4x+4$ so we must take 4 to get the expression to work (and don't forget c)
$\displaystyle -[(x+2)^2 - 4 -5] = -[(x+2)^2-9] = 9-(x+2)^2$