Respostas

  • Usuário do Brainly
2013-05-31T21:57:24-03:00

Observe que:

 

(\text{a}+\text{b})\cdot(\text{a}-\text{b})=\text{a}^2-\text{b}^2

 

Se \text{a}=\sqrt{3} e \text{b}=\sqrt{7}, temos que:

 

\text{a}^2-\text{b}^2=(\sqrt{3})^2-(\sqrt{7})^2=3-7=-4

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