Respuesta :

[tex](f \times f)( - 9) = f( - 9) \times f( - 9) \\ f(n) = n + 1 \\ f( - 9) = - 9 + 1\\ f( - 9) = - 8 \\ f( - 9) \times f( - 9) = ( - 8) \times ( - 8) \\ = 64[/tex]

Therefore the answer is 64