216/(15-x) = 18
216 = 18(15-x)
216 = 270 - 18x
18x = 270 - 216
18x = 54
x = 54/18
x = 3
Ответ: x = 3.
216/(15-x) = 18
216 = 18(15-x)
216 = 270 - 18x
18x = 270 - 216
18x = 54
x = 54/18
x = 3
Ответ: x = 3.