<span>315-(х-17)=35
x-17=315-35
x-17=280
x=280+17
x=297</span>
52-x>31
-x>31-52
-x>-21
x<21
x=2,3,5,7,11,13,17,19
2+3+5+7+11+13+17+19=77 - сумма простых чисел
77*42%:100%=32,34
5 2/6 - 5/6 = 32/6 -5/6=27/6=9/2= 4 1/2
2 1/3 -2/3=7/3-2/3=5/3=1 2/3
4 5/9-8/9=37/9-8/9=29/9= 3 2/9
3 1/2 -1 5/12=7/2-17/12=42/12-17/12=25/12= 2 1/12
6 3/7 - 5 5/7= 45/7-40/7=5/7
4 1/8 - 3 5/8 = 33/8-29/8 = 4/8=1/2