Explain how to solve 3^x-4=6 using the change of base formula (x minus 4 is the exponent not just x) !

  x ≈ 5.63093

Step-by-step explanation:

Taking the log to the base 3, you have ...

  x -4 = log₃(6)

Using the change of base formula, this becomes ...

  x -4 = log(6)/log(3) . . . . . . where the log is to any consistent base

  x = 4 + log(6)/log(3) = 4 +0.77815/0.47712

  x ≈ 5.63093

_____

The "change of base" formula tells you ...

__

In general, function arguments need parentheses if there is the least possibility of ambiguity. Exponents need parentheses if any arithmetic operation is involved. You equation is better written as ...

  3^(x-4) = 6

or typeset as ...