Question

a3+b3 =600, a + b = 10. Найдите ab.

Answer 1

a^3 + b^3 = 600
(a + b)(a^2 -ab + b^2) = 600
10((a + b)^2 - 2ab - ab) = 600
((a + b)^2 - 2ab - ab) = 60
100 - 3ab = 60
3ab = 40
ab = 40/3
ab = 13,33