(25+х)*4=360
25+х=360:4
25+х=90
х=90-25
х=65
Проверка
(25+65)*4=360
90*4=360
360=360
х-(420:6)=349
х-70=349
х=349+70
х=419
Проверка
419-(420:6)=349
419-70=349
349=349
110.000, 1.010.000 и 110.000.000
2.5+2.5+2х=7.4
5+2х=7.4
2х=7.4-5
2х=2.4
2.4/2
Ответ:1.2
4 3/5+2 5/7+5 9/35=4 21/35 + 2 25/35 + 5 9/35 = 11 55/35 = 12 20/35 = 12 4/7
1 2/3+6 4/15+8 17/45= 1 30/45 + 6 12/45 + 8 17/45 = 15 53/45 = 16 8/45
8 3/40+12 11/20+6 7/80 = 8 6/80 + 12 44/80 + 6 7/80 = 26 57/80
<u>33/4</u>а-<u>22/4</u>а+<u>13/4</u>а=<u>11/4</u>а+<u>13/4</u>а =<u>24/4</u>а =6а
6а=6· 3,12= 18,72