64/112=2.8/4 Х-3.1


/-дробная черта

Дано:64/112 = 2.8/4 Х-3.1Решение:64/112 = 16/28(сократим) = 4/72,8/4 = 7/103,1 = 3 1/104/7 = 7/10X - 3 1/107/10X = 4/7 + 3 1/107/10X = 40/70 + 3 7/707/10X = 3 47/707/10X = 257/70X = 257/70 : 7/10 = 257/70 * 10/7=257/7 * 1/7 = 257/49 = 5 12/49