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Match each combination to the corresponding value.

Two real-valued functions, [tex]f(x)[/tex] and [tex]g(x)[/tex], are defined as [tex]f(x)=x^2+6x+9[/tex] and [tex]g(x)=x^2-9[/tex]. Find the results of combining these functions.

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

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

C. [tex]\((f \times g)(x)\)[/tex]

1. [tex]2x(x+3)[/tex]

2. [tex]x^4+6x^3-54x-81[/tex]

3. [tex]6(x+3)[/tex]

4. [tex]0[/tex]

Choose the correct match:
A. [tex]\( \square \)[/tex]
B. [tex]\( \square \)[/tex]
C. [tex]\( \square \)[/tex]


Sagot :

To find the results of combining the functions [tex]\(f(x)\)[/tex] and [tex]\(g(x)\)[/tex] for a specific value of [tex]\(x\)[/tex], we will evaluate the functions for [tex]\(x = 4\)[/tex] and then compute the combined functions [tex]\((f+g)(x)\)[/tex], [tex]\((f-g)(x)\)[/tex], and [tex]\((f \times g)(x)\)[/tex].

### Step-by-Step Solution:

1. Define the Functions:
[tex]\[ f(x) = x^2 + 6x + 9 \][/tex]
[tex]\[ g(x) = x^2 - 9 \][/tex]

2. Evaluate [tex]\(f(x)\)[/tex] and [tex]\(g(x)\)[/tex] at [tex]\(x = 4\)[/tex]:
[tex]\[ f(4) = 4^2 + 6(4) + 9 = 16 + 24 + 9 = 49 \][/tex]
[tex]\[ g(4) = 4^2 - 9 = 16 - 9 = 7 \][/tex]

3. Combine the Functions:
[tex]\[ (f + g)(x) = f(x) + g(x) \][/tex]
[tex]\[ (f - g)(x) = f(x) - g(x) \][/tex]
[tex]\[ (f \times g)(x) = f(x) \times g(x) \][/tex]

4. Evaluate the Combinations at [tex]\(x = 4\)[/tex]:
[tex]\[ (f + g)(4) = f(4) + g(4) = 49 + 7 = 56 \][/tex]
[tex]\[ (f - g)(4) = f(4) - g(4) = 49 - 7 = 42 \][/tex]
[tex]\[ (f \times g)(4) = f(4) \times g(4) = 49 \times 7 = 343 \][/tex]

### Matching Each Combination to the Value:

1. [tex]\((f+g)(4) = 56\)[/tex]
2. [tex]\((f-g)(4) = 42\)[/tex]
3. [tex]\((f \times g)(4) = 343\)[/tex]

Thus, the results for the combined functions are:

[tex]\( (f+g)(4) = 56 \\ (f-g)(4) = 42 \\ (f \times g)(4) = 343 \\ \)[/tex]

Each combination is matched to its corresponding value as:

- [tex]\((f + g)(4) \rightarrow 56\)[/tex]
- [tex]\((f - g)(4) \rightarrow 42\)[/tex]
- [tex]\((f \times g)(4) \rightarrow 343\)[/tex]

So, ensuring that these combinations are correctly matched with the values given:

1. [tex]\( (f+g)(x) \rightarrow 6(x+3) \rightarrow 56 \)[/tex]
2. [tex]\( (f-g)(x) \rightarrow 2x(x+3) \rightarrow 42\)[/tex]
3. [tex]\( (f\times g)(x) \rightarrow x^4+6x^3-54 x-81 \rightarrow 343\)[/tex]