14. log₃(16 - x²) - log₃(x + 2) = log₃(7 - 2x) 15. log₅²x - 2log₅x - 3 = 0 16. 4·10⁰ˣ - 13·10ˣ + log₋ₓ(₋ₓ)³ = 0