10. log√₇ (1 – 2x) + log√₇ (x – 5) = 2 11. log₆ (3 – 2x) + log₆ (3x + 1) = 1/log₅ 6 12. ln(x + 6) = ln(12 – 4x) – ln(5 – x) 13. log₄ (x² – 3x – 10) – log₄ (4x + 8) = 0