Answer:
And for this case we can begin completing the square like this:
[tex] f(x) = x^2 +10x + (10/2)^2 +21 -(10/2)^2[/tex]
And after aggrupate the terms we got:
[tex] f(x) = (x+5)^2 +21 -25 [/tex]
And finally we have:
[tex] f(X)= (x+5)^2 -4[/tex]
And for this case our vertex would be:
[tex] (h,k) = (-5,-4) [/tex]
Step-by-step explanation:
For this case we have the following equation given:
[tex] f(x) = x^2 +10x +21[/tex]
And we want to find a formula in terms in the vertex form given by:
[tex] f(x) = a(x-h)^2 +k[/tex]
And for this case we can begin completing the square like this:
[tex] f(x) = x^2 +10x + (10/2)^2 +21 -(10/2)^2[/tex]
And after aggrupate the terms we got:
[tex] f(x) = (x+5)^2 +21 -25 [/tex]
And finally we have:
[tex] f(X)= (x+5)^2 -4[/tex]
And for this case our vertex would be:
[tex] (h,k) = (-5,-4) [/tex]