High School

If [tex]$f(x)=\left(\frac{1}{7}\right)\left(7^x\right)$[/tex], what is [tex]$f(3)$[/tex]?

A. 343
B. [tex]$\frac{1}{343}$[/tex]
C. [tex][tex]$\frac{1}{49}$[/tex][/tex]
D. 49

Answer :

To find [tex]\( f(3) \)[/tex] for the function [tex]\( f(x) = \left(\frac{1}{7}\right)\left(7^x\right) \)[/tex], we'll follow these steps:

1. Identify the Function: The function given is [tex]\( f(x) = \left(\frac{1}{7}\right)\left(7^x\right) \)[/tex].

2. Substitute [tex]\( x = 3 \)[/tex] into the Function:
- We replace [tex]\( x \)[/tex] with 3 in the function, which gives us:
[tex]\[
f(3) = \left(\frac{1}{7}\right)\left(7^3\right)
\][/tex]

3. Calculate [tex]\( 7^3 \)[/tex]:
- Calculate [tex]\( 7^3 \)[/tex], which is [tex]\( 7 \times 7 \times 7 = 343 \)[/tex].

4. Multiply by [tex]\( \frac{1}{7} \)[/tex]:
- Now, multiply [tex]\( 343 \)[/tex] by [tex]\(\frac{1}{7}\)[/tex]:
[tex]\[
\frac{1}{7} \times 343 = 49
\][/tex]

5. Conclusion:
- Therefore, [tex]\( f(3) = 49 \)[/tex].

So, the correct answer is [tex]\( D. \, 49 \)[/tex].