Question

If a+b= -1 then the value of a^3+b^3 - 3ab= ?

Answer 1

-1

Explanation:

`(a + b)^(3) = {a}^(3) + {b}^(3) + 3ab(a + b) \\ ( - 1)^(3) = {a}^(3) + {b}^(3) + 3ab( - 1) \\ - 1 = {a}^(3) + {b}^(3) - 3ab\\ \\ \huge \red{ \boxed{{a}^(3) + {b}^(3) - 3ab = - 1}}`