Question

If a + b =1 then prove that a^3 + b^3 + 3ab = 1

Answer 1

(a+b)^3 = (1)^3

a^3 + b^3 + 3ab (a+b) = 1

we know that,a+b = 1

a^3 +b^3 + 3ab ( 1 )= 1

so,

a^3 + b^3 + 3ab = 1