The expression can be simplified by finding a common denominator for each fraction pair:
12/13-15/26 = (24/26) - (15/26) = (24-15)/26 = 9/269/28-11/35 = (135/140) - (88/140) = (135-88)/140 = 47/14039/40-19/28 = (1092/1120) - (760/1120) = (1092-760)/1120 = 332/1120 = 83/280
Therefore, the simplified expression is 9/26, 47/140, 83/280.
The expression can be simplified by finding a common denominator for each fraction pair:
12/13-15/26 = (24/26) - (15/26) = (24-15)/26 = 9/26
9/28-11/35 = (135/140) - (88/140) = (135-88)/140 = 47/140
39/40-19/28 = (1092/1120) - (760/1120) = (1092-760)/1120 = 332/1120 = 83/280
Therefore, the simplified expression is 9/26, 47/140, 83/280.