Решите уравнение 5/7×(21/20-x)+16/21:8/7=1 1/4

5/7 * (21/20 - х) + 16/21 : 8/7 = 1 1/45/7 * (21/20 - х) + 16/21 * 7/8 = 5/45/7 * (21/20 - х) + 112/168 = 5/45/7 * (21/20 - х) + 14/21 = 5/45/7 * (21/20 - х) + 2/3 = 5/45/7 * (21/20 - х) = 5/4 - 2/35/7 * (21/20 - х) = 15/12 - 8/125/7 * (21/20 - х) = 7/1221/20 - х = 7/12 : 5/721/20- х = 7/12 * 7/521/20 - х = 49/60- х = 49/60 - 21/20- х = 49/60 - 63/60- х = - 14/60х = 14/60х = 7/30проверка:5/7 * (21/20 - 7/30) + 16/21 : 8/7 = 1 1/45/7 * (63/60 - 14/60) + 16/21 * 7/8 = 1 1/45/7 * 49/60 + 112/168 = 1 1/4245/420 + 14/21 = 1 1/449/84 + 56/84 = 1 1/4105/84 = 1 1/41 21/84 = 1 1/41 1/4 = 1 1/4