9/56-(7/15-5/12)*(3/14+1/2)=7/56
по действиям
1)7/15-5/12=28/60-25/60=3/60=1/20
2) 3/14+1/2=3/14+7/14=10/14=5/7
3)1/20*5/7=1/4*1/7=1/28
4) 9/56-1/28=9/56-2/56=7/56
(2 1/2)² *8/15-5/9=(5/2)² *8/15-5/9=25/4*8/15-5/9=25/1*2/15-5/9=5/1*2/3-5/9=
=10/3-5/9=30/9-5/9=25/9=2 7/9
(2 1/3*1 2/7)³ *2/9=(7/3*9/7)³ *2/9=(1/3*9/1)³ *2/9=(1/1*3/1)³ *2/9=3³ *2/9=
=3³*2/(3²)=3*2=6