Answer:
-5/48
Explanation:
(8 · 2⁷ˣ)⁴ = (1/16)⁵ˣ · 128
Take log of both sides.
log (8 · 2⁷ˣ)⁴ = log ((1/16)⁵ˣ · 128)
Use log exponent/product rules.
4 log (8 · 2⁷ˣ) = log (1/16)⁵ˣ + log 128
Use log exponent/product rules.
4 (log 8 + log (2⁷ˣ)) = 5x log (1/16) + log 128
Use log exponent rule.
4 (log 8 + 7x log 2) = 5x log (1/16) + log 128
Distribute.
4 log 8 + 28x log 2 = 5x log (1/16) + log 128
Write as powers of 2.
4 log 2³ + 28x log 2 = 5x log (2⁻⁴) + log 2⁷
Use log exponent rule.
12 log 2 + 28x log 2 = -20x log 2 + 7 log 2
Combine like terms.
5 log 2 + 48x log 2 = 0
Divide by log 2.
5 + 48x = 0
Solve for x.
x = -5/48