1) 280:х=140
х=2
2) (900-700)*у=600
200*у=600
у = 3
1) 1,2 = 1 целая 2/10 = 1 целая 1/5 = 6/5
1 целая 2/3 = 5/3
у : 6/5 = 5/3
у = 5/3 * 6/5
у = 2
--------------------------------------
Проверка 2 : 6/5 = 2 * 5/6 = 10/6 = 1 целая 4/6 = 1 целая 2/3
2) 9/20 = 45/100 = 0,45
0,6х = 0,45
х = 0,45 : 0,6
х = 0,75
---------------------------------------
Проверка: 0,6 * 0,75 = 0,45
3) 0,5 = 5/10 = 1/2
5/6у = 1/2
у = 1/2 : 5/6
у = 1/2 * 6/5 = 6/10 = 3/5
----------------------------------------
Проверка: 5/6 * 3/5 = 3/6 = 1/2
360..........................
<span>30617 </span>
<span>30617/17 = 1801 </span>
<span>3+0+6+1+7 = 17</span>