High School

If [tex]$f(x)=\left(\frac{1}{9}\right)\left(9^x\right)$[/tex], what is [tex]$f(3)$[/tex]?

A. 729
B. [tex]$\frac{1}{81}$[/tex]
C. [tex][tex]$\frac{1}{729}$[/tex][/tex]
D. 81

Answer :

To find [tex]\( f(3) \)[/tex] for the function [tex]\( f(x) = \left(\frac{1}{9}\right)\left(9^x\right) \)[/tex], follow these steps:

1. Substitute [tex]\( x = 3 \)[/tex] into the function:
[tex]\[
f(3) = \left(\frac{1}{9}\right)\left(9^3\right)
\][/tex]

2. Calculate [tex]\( 9^3 \)[/tex]:
[tex]\[
9^3 = 9 \times 9 \times 9 = 729
\][/tex]

3. Substitute the value of [tex]\( 9^3 \)[/tex] into the equation:
[tex]\[
f(3) = \left(\frac{1}{9}\right) \times 729
\][/tex]

4. Now, divide 729 by 9:
[tex]\[
\frac{729}{9} = 81
\][/tex]

So, the value of [tex]\( f(3) \)[/tex] is [tex]\(\boxed{81}\)[/tex], which corresponds to option D.