Three quadratic functions are given below:

I. [tex]f(x) = (x+2)^2 + 5[/tex]

II.
[tex]\[
\begin{tabular}{|c|r|r|r|r|r|r|}
\hline $x$ & -4 & -3 & -2 & -1 & 0 & 1 \\
\hline $g(x)$ & -3 & 2 & 5 & 5 & 2 & -3 \\
\hline
\end{tabular}
\][/tex]

III. [Description of the third function is missing]

Which of these functions have the same vertex?

1. I and II only
2. II and III only
3. I and III only
4. I, II, and III



Answer :

To determine which of the given quadratic functions have the same vertex, let's analyze each function individually.

### Function I: [tex]\( f(x) = (x + 2)^2 + 5 \)[/tex]

Rewriting the function in vertex form [tex]\( f(x) = a(x - h)^2 + k \)[/tex]:

- [tex]\( f(x) = (x + 2)^2 + 5 \)[/tex]
- Comparing, we get [tex]\( a = 1 \)[/tex], [tex]\( h = -2 \)[/tex], and [tex]\( k = 5 \)[/tex].

So, the vertex of [tex]\( f(x) \)[/tex] is [tex]\( (-2, 5) \)[/tex].

### Function II: Given data

[tex]\[ \begin{tabular}{|c|r|r|r|r|r|r|} \hline $x$ & -4 & -3 & -2 & -1 & 0 & 1 \\ \hline $g(x)$ & -3 & 2 & 5 & 5 & 2 & -3 \\ \hline \end{tabular} \][/tex]

To find the vertex of this function, we need to determine the maximum (or minimum) point. From the table, we see that the maximum value of [tex]\( g(x) = 5 \)[/tex] occurs at two points: [tex]\( x = -2 \)[/tex] and [tex]\( x = -1 \)[/tex].

For a quadratic function to be symmetric, the vertex lies exactly halfway between these points. Thus, the x-coordinate of the vertex is:
[tex]\[ x = \frac{-2 + (-1)}{2} = \frac{-3}{2} = -1.5 \][/tex]

Substituting [tex]\( x = -1.5 \)[/tex] into the function would confirm a y-value, but we can see directly from the symmetrically placed values around [tex]\( x = -1.5 \)[/tex] that the y-coordinate of the vertex remains at 5.

So, the vertex of [tex]\( g(x) \)[/tex] is [tex]\( (-1.5, 5) \)[/tex].

### Function III: Not enough information

Since no specific details or data points are given for function III, we cannot determine the exact vertex without additional information.

### Comparing Vertices

- Vertex of [tex]\( f(x) \)[/tex] (Function I): [tex]\( (-2, 5) \)[/tex]
- Vertex of [tex]\( g(x) \)[/tex] (Function II): [tex]\( (-1.5, 5) \)[/tex]
- Function III: No vertex data provided

### Conclusion

Given the above analyses, Functions I and II do not have the same vertex. There is no information available for Function III to compare its vertex.

Thus, the correct answer is:
"The quadratic functions do not have the same vertex. Therefore, none of the options 1, 2, 3, or 4 applies."