Question

if a + b is equals to 2 find a cube plus b cube

Answer 1

a + b = 2

So, (a+b)² = 4

a² + 2ab + b² = 4

a² + b² = 4 - 2ab

a³ + b³ = (a+b)(a² -ab + b²) = 2(4 - 2ab) = 8  - 4ab