Question 2 (Multiple Choice, Worth 5 Points)

The quadratic functions [tex]f(x)[/tex] and [tex]g(x)[/tex] are described as follows:

[tex]\[ f(x) = -2x^2 + 9 \][/tex]

[tex]\[
\begin{array}{|c|c|}
\hline
x & g(x) \\
\hline
0 & -5 \\
\hline
1 & 3 \\
\hline
2 & 11 \\
\hline
3 & 3 \\
\hline
4 & -5 \\
\hline
\end{array}
\][/tex]

Which statement best compares the maximum value of the two functions?

A. The maximum value is the same for both functions.
B. [tex]f(x)[/tex] has a greater maximum value than [tex]g(x)[/tex].
C. [tex]g(x)[/tex] has a greater maximum value than [tex]f(x)[/tex].
D. The maximum values cannot be determined.



Answer :

To compare the maximum values of the functions [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex], let's analyze each function step by step.

### Step 1: Analyze [tex]\( f(x) \)[/tex]

The function [tex]\( f(x) = -2x^2 + 9 \)[/tex] is a quadratic function in the form [tex]\( ax^2 + bx + c \)[/tex]. Since the coefficient of [tex]\( x^2 \)[/tex] is negative [tex]\((-2)\)[/tex], the parabola opens downwards, indicating that the vertex represents the maximum value of the function.

The vertex form of a quadratic function [tex]\( ax^2 + bx + c \)[/tex] is found at [tex]\( x = -\frac{b}{2a} \)[/tex]. For [tex]\( f(x) \)[/tex]:

- [tex]\( a = -2 \)[/tex]
- [tex]\( b = 0 \)[/tex]
- [tex]\( c = 9 \)[/tex]

The vertex lies at:

[tex]\[ x = -\frac{0}{2(-2)} = 0 \][/tex]

To find the maximum value of [tex]\( f(x) \)[/tex], substitute [tex]\( x = 0 \)[/tex] into the function:

[tex]\[ f(0) = -2(0)^2 + 9 = 9 \][/tex]

Thus, the maximum value of [tex]\( f(x) \)[/tex] is 9.

### Step 2: Analyze [tex]\( g(x) \)[/tex]

The function [tex]\( g(x) \)[/tex] is given by a table of values:

[tex]\[ \begin{array}{|c|c|} \hline x & g(x) \\ \hline 0 & -5 \\ \hline 1 & 3 \\ \hline 2 & 11 \\ \hline 3 & 3 \\ \hline 4 & -5 \\ \hline \end{array} \][/tex]

To find the maximum value of [tex]\( g(x) \)[/tex], we simply look for the highest value in the given entries. From the table:

- [tex]\( g(0) = -5 \)[/tex]
- [tex]\( g(1) = 3 \)[/tex]
- [tex]\( g(2) = 11 \)[/tex]
- [tex]\( g(3) = 3 \)[/tex]
- [tex]\( g(4) = -5 \)[/tex]

The maximum value of [tex]\( g(x) \)[/tex] is 11.

### Step 3: Compare the Maximum Values

- The maximum value of [tex]\( f(x) \)[/tex] is 9.
- The maximum value of [tex]\( g(x) \)[/tex] is 11.

By comparing these values, we see that the maximum value of [tex]\( g(x) \)[/tex] is greater than the maximum value of [tex]\( f(x) \)[/tex].

### Conclusion

The statement that best compares the maximum values of the two functions is:

[tex]\[ \boxed{\$g(x)\$ \text{ has a greater maximum value than } \$f(x)\$.} \][/tex]