Question

find the vertex. y=-x^2+2x+4

Answer 1

Complete the square!

y = -(x^2 - 2x + ____) + 4 + ____

Answer 2

what do you mean

Answer 3

I would do -b/2a

Answer 4

So, a=-1,b=2, c=4, now you are putting -b/2a
-2/-2=1, and then you will plug the value of 1 to find the corresponding y coordinate

Answer 5

\[x^2+ 2x+4\\ ( x^2+ 2x )+4\\ x^2+ 2x+( \frac{2}{2})^2 ) + 4 - ( \frac{2}{2})^2 ) \\ ( x + 1)^2 + 3 \]

Answer 6

\[ \text{ So, here, the Vertex} = ( -1,3) \]

Answer 7

luis its -x^2

Answer 8

If you Complete the Square, like Luis_Rivera just showed (except for the typo), you can PROVE -b/(2a)! Why would you NOT want to do that?

Answer 9

Because I would rather do -b/2a than the long and complicated way.

Answer 10

oh ok i got it thanks

Answer 11

Your welcome :D

Answer 12

lol