Answer if D hope it helps!
To do this, complete the square:
p(x) = 21 + 24x + 6x2 => <span>p(x) = 6x2 + 24x + 21
Rewrite the first 2 terms as
6(x^2 + 4x)
then you have </span><span>p(x) = 6(x2 + 4x ) + 21
Now complete the square of x^2 + 4x:
p(x) = 6(x^2 + 4x + 4 - 4) + 21
= 6(x+2)^2 - 24 + 21
p(x) = 6(x+2)^2 - 3 this is in vertex form now.
We can read off the coordinates of the vertex from this: (-2, -3)</span>
If you mean how do you get x by it's you divide both sides by 8, to cancel out the multiplication between x and 8, meaning that it would end up being x=7, sorry if that didn't answer your question correctly.
-4 is the first consecutive even integer following -6<span />
