Question

HELP PLEASE what are the zeros for the function f(x) = 2x2 + 8x + 10 and how many times does the graph cross the x-axis?

Answer 1

@Rushwr

Answer 2

Do you know how to factor quadratics? or use the quadratic formula?

Answer 3

i got x=-2+-i

Answer 4

is that correct?

Answer 5

yes that is correct. however that also means that the quadratic never crosses the x axis as it only has complex roots

Answer 6

Thank you so so much :))) can you help with a few more? if not its okay!

Answer 7

in this case I should say.

Answer 8

Im sure someone can help @Morgan27 Go ahead and post it :)

Answer 9

If a parabola's focus is at (−2, 4) and the directrix is at y = −2, what is the vertex form of the equation representing this parabola?

Answer 10

Oh I'm glad I checked back in oops...still need help with this one?

Answer 11

yesss i do lol thank you

Answer 12

Well just in case...
The formula we will be using is

\[\large (x - h)^2 = 4p(y - k)\]

first thing we need to find is the vertex (h,k)

The vertex is halfway between the focus and the directrix....so halfway between y = 4 and y = -2 would be at y = 1

So we know the vertex is located at (-2,1)

Now we just need the distance from the vertex to the focus...which is 3 (p)

Now we have everything we need

\[\large (x - (-2))^2 = 4(3)(y - 1)\]
\[\large (x + 2)^2 = 12(y - 1)\]

Now we just solve for 'y'

\[\large y = \frac{1}{12}(x + 2)^2 + 1\]

Answer 13

y=4/3?

Answer 14

Huh? We just needed the vertex form of the equation :)

Answer 15

ohhhh lol im sorry

Answer 16

No problem at all :)

Answer 17

\[y=(x+2)^2+\frac{ 1 }{ 12 }+1\]

Answer 18

Nope...the 1/12 is multiplied to the (x+2)^2

Answer 19

i got it now. Thank you for all of your help! :)

Answer 20

Sorry for the REALLY late reply but you're welcome :)