Question

The graph of which quadratic equation is shown below?



y = −x2 + 6x + 8

y = −x2 − 6x + 8

y = x2 + 6x + 8

y = x2 − 6x + 8

Answer 1

well the equation is opening upward, so we know from that that it has a positive x^2 value

Answer 2

so that eliminates half the choices

Answer 3

so would it be c?

Answer 4

according to the graph, there is a ponit, (-3, -1) so what i would do is plug that into the equation to see which one is true

Answer 5

the parabola follows teh equation \[ \large y = a(x –\color{red} h)^2 + \color{red}k\] and your vertex \[\large v=\color{red}{(-3,-1)}\]

Answer 6

\[-1=x^2+6x+8\]
\[-1=(-3)^2+6(-3)+8\]
\[-1=9-18+8\]
\[-1=-1\]

Answer 7

\[-1=(-3)^2-6(-3)+8\]
\[-1=9+18+8\]
\[-1\neq 35\]

Answer 8

Does it make sence @sumsumjoe

Answer 9

*sense

Answer 10

after plugging in the points of your vertex, expand the equation. \[\large y=(x+3)^2+1\]\[\large y=(x+3)^2-1\]\[\large y=x^2+6x+9-1\]\[\large y=x^2+6x+8\]

Answer 11

And watch out for this girl :P
She's great at explaining

Answer 12

You're welcome joe :l

Answer 13

xD

Answer 14

Ans thank you Miss Jhan for reminding me about the vertex

Answer 15

No problem :)