Here is one that is worked exactly the same way.  Use it as
a model for yours:

 = 64

Note that  is 4-1 and that 64 = 43

(4-1)2x = 43

Remove the parentheses on the left by multiplying exponents

4-2x = 43

Since the base 4 is the same on both sides, and it is positive and not 1,
the exponents will be equal too, so we can write

-2x = 3

and then divide both sides by -2 and get

  x = 

Edwin