Answer
35.6
Work Step by Step
Using the rules of logarithms to solve the equation, we find:
$$\log _4\left(2x\right)=\frac{40}{13} \\ \log _4\left(2x\right)=\log _4\left(64\cdot \:4^{\frac{1}{13}}\right) \\ x=32\cdot \:4^{\frac{1}{13}} \\ x=35.6$$
Checking for extraneous solutions, we see that the given solution is valid.