1
...(59-41)(59²+59*41+41²)/18 + 59*41=18*(59²+59*41+41²)/18 + 59*41=
=59²+59*41+41²+59*41=59²+2*59*41+41²=(59+41)²=100²=10000
2
1)...=(97+83)(97²-97*83+83²)/180 - 97*83=180*(97²-97*83+83²)/180 - 97*83=
=97²-97*83+83² -97*83=97²-2*97*83+83²=(97-83)²=14²
2)...=(35-28)(35+28)=7*63
3)14²:7*63=(14*14)/(7*63)=(2*2)/(1*9)=4/9