Cho a > 0, b > 0, c > 0 thỏa mãn (1/a) + (2/b) + (3/c) = 3. Chứng minh rằng (27a^2/c(c^2 + 9a^2)) + (b^2/a(4a^2 + b^2)) + (8c^2/b(9b^2 + 4c^2)) > 3/2