Владимир7 лет назад
а) 4/7 + (-11/14) = 4/7 - 11/14 = 2 * 4/(7 * 2) - 11/14 = 8/14 - 11/14 = (8 - 11)/14 = -3/14;
Ответ: -3/14.
б) -4/9 - 5/12 = -4 * 4/(9 * 4) - 3 * 5/(12 * 3) = -16/36 - 15/36 = -(16 + 15)/36 = -31/36;
Ответ: -31/36.
в) -14/25 * 20/21 = -(14 * 20)/(25 * 21) = -(2 * 7 * 5 * 4)/(5 * 5 * 3 * 7) = -(2 * 4)/(5 * 3) = -8/15;
Ответ: -8/15.
г) 14/9 : (-17/15) = 14/9 * (-15/17) = -(14 * 15)/(9 * 17) = -(14 * 3 * 5)/(3 * 3 * 17) = -70/51.
Ответ: -70/51.