Разбираемся:
(8ab) / (a + 8b) * (a / (8b) - (8b) / a) = (8ab) / (a + 8b) * (a2 - (8b)2) / (8ab) = (a2 - (8b)2) / (a + 8b) = (a - 8b)(a + 8b) / (a + 8b) = a - 8b
При a = 8√3 + 7, b = √3 - 3:
8√3 + 7 - 8(√3 - 3) = 8√3 + 7 - 8√3 + 24 = 31
Ответ: 31