1 2/5 : 5/7 + 3/8 = 7/5 * 7/5 + 3/8 = 49/25 + 3/8 = (392+75)/200 = 467/200 = 2 67/200 = 2,335
5,1х-0,03-2,01=0
5,1х=2,04
х=2,04:5,1
х=0,4
7,3у=20,9+3,5
7,3у=24,4
у=24,4/7,3
у=3,3
3 3/7 : 1 1/56 - 3 5/21 : 1 22/63 =
= 24/7 × 56/57 - 68/21 × 63/85=
= ( 8×8) / (1×19) - ( 4×3)/ (1×5)=
= 64/19 - 12/5= ( 320-228)/95 = 92/95