-0,6х=1,8х-7,2
-2,4х=-7,2|:(-2,4)
х=+3
Ответ: 3.
1)28*5=140
2)25*4=100
3)120:2=60
4)140+100-60=180
5)180:6=30
6)500-30=470
7)28:4=7
8)420:140=3
9)7+3=10
10)10*30=300
11)470-300=170
Ответ:170
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40.
Ответ: 9001169.
Вот вроде