(a + b)/2 = 6
(a + b)^2 = a^2 + b^2 + 70
Получаем
a + b = 12
(a + b)^2 = 144 = a^2 + b^2 + 70
a^2 + b^2 = 144 - 70 = 74
С другой стороны
b = 12 - a
a^2 + (12 - a)^2 = 74
a^2 + 144 - 24a + a^2 - 74 = 0
2a^2 - 24a + 70 = 0
a^2 - 12a + 35 = 0
(a - 5)(a - 7) = 0
a = 5; b = 7
a = 7; b = 5
Ответ: 5 и 7