<span>16 с + 20=7 с + 74</span>
<span>16с-7с=74-20</span>
<span>9с=54</span>
<span>с=54:9</span>
<span>с=6</span>
<span>Ответ:6</span>
<span>Проверка:</span>
<span>16*6+20=7*6+74</span>
<span>116=116</span>
<span>5целых2/5*(-1целая1/9)= 27\5 х (-10\9)= -27х10\5х9= -3х2\1х1=-6</span>
<span>1)90*4=560(м) 2)560:36=15,10 (мин)
Во :)</span>