Tolong dijawab ya.....

[tex] (a + b {)}^{3} = \\ = (a + b)(a + b {)}^{2} \\ = a( {a}^{2} + 2ab + {b}^{2} ) + b( {a}^{2} + 2ab + {b}^{2} ) \\ = {a}^{3} + {3a}^{2} b + 3a {b}^{2} + {b}^{2} \\ = 1 + 3 + 3 + 1 [/tex]

smogaa membantuu:D