Решение
a) [(m - 4)/(m + 4) - (m + 4)/(m - 4)] * (m² - 16)/16 =
{[m - 4)² - (m + 4)²] / (m² - 16)} * [(m² - 16)/16] =
= (m² - 8m + 16 - m² - 8m - 16) / 16 = - 16m / 16 = - m
б) [7 / (b + 7) + (b² + 49) / (b² - 49) - 7 / (b - 7)] : (b + 1) / 2 =
= [(7b - 49 + b² + 49 - 7b - 49) / (b² - 49)] : (b + 1) / 2 =
= [(b² - 49) / (b² - 49)] : (b + 1) / 2 = 2 / (b + 1)