2) (3 2/7 + 4 5/21) * (51/49 + 9/16 - 18/224)

3 2/7 = 23/7, 4 5/21 = 89/21. 23/7 + 89/21 = 69/21 + 89/21 = 158/21. 51/49 + 9/16 - 18/224 = 168/224 + 126/224 - 18/224 = 276/224 = 69/56. Итог: (158/21) * (69/56) = 10902/1176 = 9.27.