Функция f(x) нечетная, поэтому f(–x) = –f(x).

1) f(8) – f(–8) = 0

f(8) + f(8) = 0

2·f(8) = 0

f(8) = 0

2) f(3) · f(–3) = –1

–f(3)·f(3) = –1

f²(3) = 1

f(3) = ±1