Х+800=5х
4х=800
х=200
Ответ: при х=200
1)5860:10 58600:10
586 =586
2)23000*4 и 2300*400
92000 <920000
3)2400:60и 2400:600
40> 4
4)1530*20 и 153*200
30600 =30600
5)840:20720<840:10
6)16*40 и 32*20
640= 640
A + b = 13 | ^2
a^2 +2ab +b^2 = 169
a^2 +b^2 +2ab = 169
101 +2ab = 169
2ab = 169 - 101
2ab= 68
ab= 68:2 = 34
ab = 34