Answer:
x ≈ 5.63093
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
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The "change of base" formula tells you ...

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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 ...
