Определите знак произведения:
а) (−1) * (−1);
б) (−1) * (−1) * (−1);
в) (−1) * (−1) * (−1) * (−1);
г) (−1) * (−1) * (−1) * (−1) * (−1) * (−1) * (−1).
Решение:
а) (−1) * (−1) = 1;
б) (−1) * (−1) * (−1) = ((−1) * (−1)) * (−1) = 1 * (−1) = −1;
в) (−1) * (−1) * (−1) * (−1) = ((−1) * (−1)) * ((−1) * (−1)) = 1 * 1 = 1;
г) (−1) * (−1) * (−1) * (−1) * (−1) * (−1) * (−1) = ((−1) * (−1)) * ((−1) * (−1)) * ((−1) * (−1)) * (−1) = 1 * 1 * 1 * (−1) = −1.
Ответ:
а) +;
б) −;
в) +;
г) −.