2,1/2у это 2целых 1/2 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 2,3у+31+2,1/2у=67 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
2 целых 1/2 = 2,5 в десятичных дробях -------------------------------------------------------- 2,3у + 31 + 2,5у = 67 2,3у + 2,5у = 67 - 31 4,8у = 36 у = 36 : 4,8 у = 7,5 Проверка: 2,3 * 7,5 + 31 + 2,5 * 7,5 = 67 17,25 + 31 + 18,75 = 67 67 = 67
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