Ответы: 1
2017-11-15 12:38
A — b = (a — b)(a + ab + b) (a — b) = 25 a — 2ab + b = 25 a + b = 25 + 2ab = 25 + 2 * 1 = 27 a — b = 5 *(27 + 1) = 5 * 28 = 140