What value for x makes the equation true?

Since we already have 3^7 you should know that 3 times 3 is 9. Here is how I would simplify it.
3^7 times 3^4 times 3^3
You should add all the exponents and get
3^14
27 is basically 3 times 3 times 3 which is why I chose to put 27 that way