Find all real x that satisfy \[\large 9^x - 4 \cdot 3^x + 6 - \frac{4}{3^x} + \frac{1}{9^x} = 0\]
I will give you 2 good hints.
You can come back with your thoughts if you need more help.
1) let y=3^x
2) \((a-b)^4=a^4-4a^3b+6a^2b^2-4ab^3+b^4\)