900 - 12(x/30 + 52) = 180900 - 12x/30 - 1252 = 180900 - 12x/30 - 624 = 180276 - 12x/30 = 180-12x/30 = 180 - 276-12x/30 = -96-12x = -96*30-12x = -2880x = -2880 / -12x = 240
Ответ: x = 240.
900 - 12(x/30 + 52) = 180
900 - 12x/30 - 1252 = 180
900 - 12x/30 - 624 = 180
276 - 12x/30 = 180
-12x/30 = 180 - 276
-12x/30 = -96
-12x = -96*30
-12x = -2880
x = -2880 / -12
x = 240
Ответ: x = 240.