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( a+B+c) la puterea -2

Răspuns :

Răspuns:

[tex]\dislaystyle \boxed{ x^{ - n} \ = \frac{1}{ x^{n} } }[/tex]

[tex]\displaystyle (a \ + \ b \ + c) ^{-2} = \ \frac{1}{ (a \ + \ b \ + c) ^{2} } \ = \frac{1}{ a^{2} \ + \ b^{2} \ + \ c^{2} \ + \ 2ab\ + \ 2bc \ + \ 2ac }[/tex]