<span>55:5-5-5=1; </span>
<span>(5-5)*5*5*5=0; </span>
<span>(5+5+5-5):5=2; </span>
<span>(5-5:5-5:5)=3; </span>
<span>(5+5+5+5):5=4: </span>
<span>5*5-5*5+5=5; </span>
<span>(5+5):(5+5)+5=6; </span>
<span>5:5+5:5 +5=7; </span>
<span>(5+5+5):5+5=8; </span>
<span>(55-5-5):5=9: </span>
<span>55:5-5:5=10</span>
Х - 1-ая полка
х +3 - 2 полка
(х+3)+6 - 3 полка
х+х +3+х+3+6=48
3х+12=48
3х=48-12
3х=36
х =12 книг на 1 полке