Question

пожалуйста.дам 10 баллов :)​

Answer 1

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Answer 2

Ответ:

a)3/55 б)141/5 в)75/14

Объяснение:

a)48^2-45^2=(45+3)^2-45^2=45^2+270+9-45^2=270+9=279

74^2-19^2=74^2-(74-55)^2=74^2-74^2+2*74*55-55^2=2*74*55-55^2=55(148-55)=55*93

279/55*93=93*3/55*93=3/55

б)(88^2-53^2)/(20^2-15^2)

(88^2-53^2)=(53+35)^2-53^2=53^2+2*53*35 +35^2-53^2=2*53*35 +35^2=35(2*53+35)=35*141

(20^2-15^2)=(15+5)^2-15^2=15^2+2*15*5+5^2-15^2=2*15*5+5^2=5(30+5)=5*35

(88^2-53^2)/(20^2-15^2)=35*141/5*35=141/5

в)(89^2-61^2)/(89^2-2*89*61+61^2)=(89^2-61^2)/(89-61)^2=(89-61)(89+61)/(89-61)^2=(89+61)/(89-61)=150/28=75/14