Solve 9^(3 - x) = 81^(4 - 2x).
9^(3-x) = 9^2(4-2x)
equate the exponents
3-x = 8-4x
3x = 5
x = 5/3
Another way:
If you take the LOG of both sides you will get this:
(3-x) Log 9 = (4-2x) log 81
(3-x)/(4-2x) = log81/log9
(3-x)/(4-2x) = 2
-5 = -3x
+36916 
