(240 - 2 * х) : 30 = 7
240 - 2 * х = 7 * 30
240 - 2 * х = 210
2 * х = 240 - 210
2 * х = 30
х = 30 : 2
х = 15
Проверка: (240 - 2 * 15) : 30 = 7
(240 - 30) : 30 = 7
210 : 30 = 7
7 = 7
Решение:
1) 432.680:58=7.460
2) 193.103:629=307
3) 2.804.620:460=6.097
Проверка:
1) 7.460*58=432.680
2) 307*629=193.103
3) 6.097*460=2.804.620
X+25>40
x>40-25
x>15
[15;+∞)