Which statement best describes how to determine whether [tex]f(x) = 9 - 4x^2[/tex] is an odd function?

A. Determine whether [tex]9 - 4(-x)^2[/tex] is equivalent to [tex]9 - 4x^2[/tex].
B. Determine whether [tex]9 - 4\left(-x^2\right)[/tex] is equivalent to [tex]9 + 4x^2[/tex].
C. Determine whether [tex]9 - 4(-x)^2[/tex] is equivalent to [tex]-\left(9 - 4x^2\right)[/tex].
D. Determine whether [tex]9 - 4\left(-x^2\right)[/tex] is equivalent to [tex]-\left(9 + 4x^2\right)[/tex].



Answer :

To determine whether a function [tex]\( f(x) \)[/tex] is an odd function, we need to check if [tex]\( f(-x) = -f(x) \)[/tex]. Let's go through the steps for [tex]\( f(x) = 9 - 4x^2 \)[/tex]:

1. First, find the expression for [tex]\( f(-x) \)[/tex]:
[tex]\[ f(-x) = 9 - 4(-x)^2 \][/tex]
Simplifying this expression:
[tex]\[ f(-x) = 9 - 4(x^2) = 9 - 4x^2 \][/tex]

2. Next, find the negative of the original function, [tex]\( -f(x) \)[/tex]:
[tex]\[ -f(x) = -(9 - 4x^2) = -9 + 4x^2 \][/tex]

3. Compare [tex]\( f(-x) \)[/tex] and [tex]\( -f(x) \)[/tex]:
[tex]\[ f(-x) = 9 - 4x^2 \][/tex]
[tex]\[ -f(x) = -9 + 4x^2 \][/tex]

Clearly, [tex]\( f(-x) \neq -f(x) \)[/tex]. Thus, the function [tex]\( f(x) = 9 - 4x^2 \)[/tex] is not an odd function.

Among the given statements, the third one is the one that best describes how to determine whether [tex]\( f(x) = 9 - 4x^2 \)[/tex] is an odd function:

Determine whether [tex]\( 9-4(-x)^2 \)[/tex] is equivalent to [tex]\( -\left(9-4 x^2\right) \)[/tex].

This statement aligns with the requirement to check if [tex]\( f(-x) = -f(x) \)[/tex].