Solve for x over the real numbers:

4^(log(x)/log(7)) = 16

Take the logarithm base 4 of both sides:

log(x)/log(7) = 2

Multiply both sides by log(7):

log(x) = 2 log(7)

2 log(7) = log(7^2) = log(49):

log(x) = log(49)

Cancel logarithms by taking exp of both sides:

**x = 49**