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Решите задачу:

$\frac{124^2-144}{239^2-1089}=\frac{124^2-12^2}{239^2-33^2}= \frac{(124-12)(124+12)}{(239-33)(239+33)}= \\ = \frac{112*136}{206*272}=\frac{112}{206*2}= \frac{56}{206}= \frac{28}{103}\\\frac{13.5^2-72.25}{73.5^2-68.5^2}=\frac{13.5^2-8.5^2}{73.5^2-68.5^2}= \frac{(13.5-8.5)(13.5+8.5)}{(73.5-68.5)(73.5+68.5)}= \\ =\frac{5*22}{5*142}= \frac{22}{142}= \frac{11}{71}$