(-2а⁶b³)³/(5a⁸b⁴)² = -8a¹⁸b⁹/25a¹⁶b⁸ = (-8/25)a²b = -0,32×(7/8)²×(-0,12) = 0,0294

(3a⁹b³)²/(-4a⁴b)⁴ = 9a¹⁸b⁶/(-256a¹⁶b⁴) = –9a²b²/256 = –9×(-5/9)²×(-16)²/256 = –25/9 = –2 7/9