а)
y + 4/15 = 2/3 ,
у = 2/3 - 4/15,
у = 10/15 - 4/15,
у = 6/15,
у = 2/5,
б)
y - 5/20 = 5/8 ,
у = 5/8 + 5/20,
у = 25/40 + 10/40,
у = 35/40,
у = 7/8,
в)
x - 2/5 = 3/7 - 8/35,
х = 3/7 - 8/35 + 2/5,
х = 15/35 - 8/35 + 14/35,
х = 21/35,
х = 3/5
а) у+4/15=2/3
у+4/15=10/15
у=10/15-4/15
у=6/15
б) у-5/20=5/8
у-10/40=25/40
у=25/40+10/40
у=35/40
