1) 61²-122*15+15² = 61²-2*61*15+15² = (61-15)² = 46² = 2116
43²-17² / 41²-19² = (43-17)(43+17) / (41-19)(41+19) = 26*60 / 22*60 = 26/22 = 1 2/11
1) 61²-122*15+15² = 61²-2*61*15+15² = (61-15)² = 46² = 2116
43²-17² / 41²-19² = (43-17)(43+17) / (41-19)(41+19) = 26*60 / 22*60 = 26/22 = 1 2/11