<span>(1,65-0,3х):0,34=4,5</span>
<span>(1,65-0,3х)=4,5*0,34</span>
<span>(1,65-0,3х)=1,53</span>
<span>-0,3х=1,53-1,65</span>
<span>-0,3х=-0,12</span>
<span>х=0,12:0,3</span>
<span>х=0,4</span>
Ответ:
7+13=20
400/20=20
7*20=140
13*20=260
140/260