Which statement verifies that [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex] are inverses of each other?

A. [tex]\( f(g(x)) = x \)[/tex]

B. [tex]\( f(g(x)) = x \)[/tex] and [tex]\( g(f(x)) = -x \)[/tex]

C. [tex]\( f(g(x)) = \frac{1}{g(f(x))} \)[/tex]

D. [tex]\( f(g(x)) = x \)[/tex] and [tex]\( g(f(x)) = x \)[/tex]



Answer :

To determine whether [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex] are inverses of each other, we need to verify two conditions:

1. [tex]\( f(g(x)) = x \)[/tex]
2. [tex]\( g(f(x)) = x \)[/tex]

These conditions ensure that applying one function after the other returns the original input, which is the definition of inverse functions.

Here’s how we verify:

### Step-by-Step Verification

1. First Condition: [tex]\( f(g(x)) = x \)[/tex]

When you apply [tex]\( g(x) \)[/tex] to an input [tex]\( x \)[/tex] and then apply [tex]\( f(x) \)[/tex] to the result, you should get back the original input [tex]\( x \)[/tex]. Mathematically, this is written as:
[tex]\[ f(g(x)) = x \][/tex]
This means that for every [tex]\( x \)[/tex] in the domain of [tex]\( g \)[/tex], [tex]\( f(g(x)) \)[/tex] returns [tex]\( x \)[/tex].

2. Second Condition: [tex]\( g(f(x)) = x \)[/tex]

Similarly, when you apply [tex]\( f(x) \)[/tex] to an input [tex]\( x \)[/tex] and then apply [tex]\( g(x) \)[/tex] to the result, you should also get back the original input [tex]\( x \)[/tex]. Mathematically, this is written as:
[tex]\[ g(f(x)) = x \][/tex]
This means that for every [tex]\( x \)[/tex] in the domain of [tex]\( f \)[/tex], [tex]\( g(f(x)) \)[/tex] returns [tex]\( x \)[/tex].

### Analysis of Given Statements

1. [tex]\( f(g(x)) = x \)[/tex]

This statement only verifies the first condition. It is necessary but not sufficient by itself for [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex] to be inverses because it does not verify the second condition.

2. [tex]\( f(g(x)) = x \)[/tex] and [tex]\( g(f(x)) = -x \)[/tex]

This statement verifies the first condition correctly. However, the second condition is incorrect because it must be [tex]\( g(f(x)) = x \)[/tex], not [tex]\( g(f(x)) = -x \)[/tex].

3. [tex]\( f(g(x)) = \frac{1}{g(f(x))} \)[/tex]

Neither of these expressions aligns with the conditions required to verify inverse functions. Thus, this statement is incorrect.

4. [tex]\( f(g(x)) = x \)[/tex] and [tex]\( g(f(x)) = x \)[/tex]

This statement verifies both conditions necessary to confirm that [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex] are indeed inverses of each other.

Given these verifications, the correct statement that verifies [tex]\( f(x) \)[/tex] and [tex]\( g(x) \)[/tex] are inverses of each other is:

[tex]\[ \boxed{4} \][/tex]

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