Question

I don’t understand need help asap please. Complete the square to determine the minimum or maximum value of the function defined by the expression a^2-2a-8 show work

Answer 1

(a-1)^2-9

Explanation:

First you divide the coefficient of a by 2, which is 1. Now, do this:
`(a-1)^2-8` where the -1 is half the coefficient of a. What this does is get the first two terms: a^2 and 2a, but we have an extra + 1(expanding this out gives
`a^2 -2a + 1`. So we have to subtract 1 to cancel it out. This gives
`(a-1)^2-9`, because -8-1=9. We can check this by expanding it out, and seeing if it equals our previous equation. Expanding this out gives
`a^2-2a+1-9`, which is equal to our originial equation.