3. 11 4 14 4 3
— + — - — = — - — = 1—
7 7 7 7 7 7
Ответ 21/1 если в столбик
<span>1)15*(е+2):7=6*(2е+7):7</span>
<span>(15е+30)/7=(12е+42)/7</span>
<span>(15е+30)*7=(12е+42)*7</span>
<span>105е+210=84е+294</span>
<span>105е-84е=294-210</span>
<span>21е=84</span>
<span>е=84/21</span>
<span>е=4</span>
<span>15*6/7=6*15/7-проверка</span>
<span>2)5*(с+3):6=8*(10-с):6</span>
<span>(5с+15)/6=(80-8с)/6</span>
<span>(5с+15)*6=(80-8с)*6</span>
<span>30с+90=480-48с</span>
<span>30с+48с=480-90</span>
<span>78с=390</span>
<span>с=390/78</span>
<span>с=5</span>
<span>5*8/6=8*5/6-проверка</span>
1) 12:3/4=12*4/3=16 - марок
2) 12:4/3=12*3/4=9 - значков
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