1)
х - 26 7/21=100 5/28
х=100 5/28+26 7/21 (НОК=7*3*4=84)
х=100 15/84+26 21/84
х=126 36/84=126 3/7
2)
х - 37 17/54=15 16/45
х=15 16/45+37 17/54 (НОК=9*5*6=270)
х=15 96/270+37 85/270
х=52 181/270
3)
х - 33 21/25=42 17/35
х=42 17/35+33 21/25 (НОК=5*7*5=175)
х=42 85/175+33 147/175
х=75 232/175=76 57/175