<span>0,6*(х+7)-0,5*(х-3)=6,8</span>
<span>0,6х+4,2-0,5х+1,5=6,8</span>
<span>0,6х-0,5х=6,8-4,2-1,5</span>
<span>0,1х=1,1</span>
<span>х=1,1:0,1</span>
<span>х=11</span>
<span>Ответ:11</span>