3^x×9^x×27^x
=3^x×3^(2x)×3^(3x)
=3^(x+2x+3x)
=3^(6x)=3^ 12
So 6x= 12.
The solution is x=2.
Where 3 x represents the x power of 3.
Hope to adopt, if you don't understand, welcome to ask questions.