9/10x5/6; 6/25x20/21; 17/30x26/51; 40/7x14/5; 57/37x74/86; 81/115x46/81; 3/16x4; 23x5/46; решите кто решит еще 20 подкину

9/10x5/6=9*5/10*6=3*1/2*2=3/4
6/25x20/21=6*20/25*21=3*4/5*7=12/35
17/30x26/51=17*26/30*51=1*13/15*3=13/45
40/7x14/5=40*14/7*5=8*2=16
57/37x74/86=57*74/37*86=57*37/37*43=57/43
81/115x46/81=81*46/115*81=46/115
3/16x4=3*4/16=3/4
23x5/46=23*5/46=5/2