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