Question

What is the value of x if $3^x+27\left(3^{-x}\right)=12?$

• A. 1
• B. 2
• C. 1 or 2
• D. 0 or 1

Answer 1

The correct option is C 1 or 2

Let x= 1 put in $3^x+27\left(3^{-x}\right)=12$

Then $3^1+27\left(3^{-1}\right)=12$

$\Rightarrow 3+27\times \frac{1}{3}=12$

$\Rightarrow 12=12$

And let x=2 then

$3^2+27\left(3^2\right)=12$

]$\Rightarrow 9+27\times \frac{1}{9}=12$

$\Rightarrow 9+3=12$

Then X =1 and x=2 is write answer