1) 3,557+x /2=4 то есть вверху дроби (3,557 + х), а внизу 2 ?
Тогда такое решение:
3,557 + х = 4 * 2
3,557 + х = 8
х = 8 – 3,557
х = 4,443
Проверка: (3,557 + 4,443) / 2 = 4
8/2 = 4
4 = 4
2) x- 0.731/3=5
х – 0,731 = 5 * 3
х – 0,731 = 15
х = 15 + 0,731
х = 15,731
Проверка: (15,731 – 0,731) / 3 = 5
15/3 = 5
5=5
3) 12.392+x/5=2.365+2.635
(12,392 + х) / 5 = 5
12,392 + х = 5 * 5
12,932 + х = 25
х = 25 – 12,392
х = 12,608
Проверка: (12,392 + 12,608) / 5 = 2,365 + 2,635
25/5=5
5=5
4) 125.95-x/2.65+4.35=6
(125,95 – х) / (2,65 + 4,35) = 6
(125,95 – х) / 7 = 6
125,95 – х = 6 * 7
125,95 – х = 42
х = 125,95 – 42
х = 83,95
Проверка: (125,95 – 83,95) / (2,65 + 4,35) = 6
42/7 = 6
6 = 6