х + 7/8х + 0,9х = 222,
х + 7/8х + 9/10х = 222,
40/40х + 35/40х + 36/40х = 222,
111/40х = 222,
х = 222 : 111/40,
х = 222 * 40/111,
х = 80
x + 7/8x + 0,9x = 222
1x + 0,875x + 0,9x = 222
2,775x = 222
x = 222 : 2,775 = 222000 : 2775
x = 80
ответ: х = 80.
х + 7/8х + 0,9х = 222,
х + 7/8х + 9/10х = 222,
40/40х + 35/40х + 36/40х = 222,
111/40х = 222,
х = 222 : 111/40,
х = 222 * 40/111,
х = 80
x + 7/8x + 0,9x = 222
1x + 0,875x + 0,9x = 222
2,775x = 222
x = 222 : 2,775 = 222000 : 2775
x = 80
ответ: х = 80.