124^2-144/ 239^2-1089 вычислите 106^2-121/122^2-64 13,5^2-72,25/ 73,5^2-68,5^2 решите

1)=124^2-12^2/239^2-33^2=(124-12)(124+12)/(239-33)(239+33)=112×136/206×272=476/1751
2)=(106-11)(106+11)/(122-8)(122+8)=95×117/114×130=741/988
3)=13,5^2-8,5^2/73,5^2-68,5^2=(13,5-8,5)(13,5+8,5)/(73,5-68,5)(73,5+68,5)=5×22/5×142=110/710=11/71