Answer:
7^(-x - 9) = 4^(4x)
(-x - 9)(log 7) = 4x(log 4)
-x log 7 - 9 log 7 = 8x log 2
x(8 log 2 + log 7) = -9 log 7
x = -(9 log 7)/(8 log 2 + log 7)
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