Respostas

A melhor resposta!
2013-02-19T19:14:59-03:00

C = 7! / 4! . (7-4)!

 

C = 7.6.5 / 3.2.1

 

C= 35

 

 

C = 8! / 2! . 6!

 

C = 8.7 / 2

 

C = 28

 

C1 + C2 = 35+28

 

C1 + C2 = 63

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  • Usuário do Brainly
2013-02-19T19:15:26-03:00

Observe que:

 

\binom{\text{n}}{\text{k}}=\dfrac{\text{n}!}{\text{k}!\cdot(\text{n}-\text{k})!}

 

Desta maneira, temos que:

 

\text{X}=\binom{7}{4}+\binom{8}{2}

 

\text{X}=\dfrac{7!}{4!\cdot3!}+\dfrac{8!}{2!\cdot6!}

 

\text{X}=35+28=63

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