Question

What is the vertex of the function y = 2x2 + 16x + 21?
The two after the x is an exponent

Answer 1

Vertex. Find x by -b/2a. Once you have x plug into equation to get y.

Answer 2

you need an equation of the form:\[y=a(x-h)^2+k\]
where (h,k) is the vertex so complete the square:
\[y=2x^2+16x+21\]
subtract 21 from both sides:\[y-21=2x^2+16x\]
factor the right hand side with 2:\[y-21=2(x^2+8x)\]
complete the square by adding 32 to both sides in the parentheses: in this case (16):\[y+11=2(x^2+8x+16)\]
now write as perfect square:\[y+11=2(x+4)^2\]
now put in vertex form:\[y=2(x+4)^2-11\]

Answer 3

can u find the vertex using vertex form from there?

Answer 4

yes thank you so much

Answer 5

did u get (-4,-11) as your vertex?

Answer 6

yes ! (:

Answer 7

Did you get what i did when i completed the square

Answer 8

because i don't just want u to get the answer without understanding how you got it

Answer 9

So LOOK at all my steps carefully and take them in

Answer 10

no i got it we learned this in class i just needed a refresher on how to do it. Thank you for the help !