Question

I need the answers as soon as you can! I’m on the clock

Answer 1

`D`

1) The first thing to do is to find the vertex. So let's do it, considering that we already have the vertex and then we can find the coefficients. Note that all functions have a=1:

`\begin{gathered} h=-(b)/(2a) \\ 9=(-b)/(2(-1)) \\ 9\cdot-2=-b \\ -b=-18 \\ b=18 \\ ----- \\ \end{gathered}`

2) Now, let's find the other coefficient "c", since we've got a,b.

`\begin{gathered} k=(-\Delta)/(4a) \\ 7=(-(18^2-4(-1)(c)))/(4(1)) \\ 28=-(324+4c) \\ 28=-324-4c \\ 28+324=-4c \\ 352=-4c \\ c=(352)/(-4) \\ c=-88 \end{gathered}`

3) Thus the answer is:

`D`