Question

me ajudem a responder A7,3+A4,2+A8,4

Answer 1

A7,3=7!/(7-3)!
A7,3= 7!/4!
A7,3=7*6*5*4!/4!
A7,3= 210
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A4,2= 4!/(4-2)!
A4,2= 4!/2!
A4,2=4*3*2!/2!
A4,2= 12
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A8,4= 8!/(8-4)!
A8,4=8!/4!
A8,4=8*7*6*5*4!/4!
A8,4= 8*7*6*5
A8,4= 1680
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210+12+1680= 1902

Answer 2

Olá.

Para resolver essa questão, devemos usar a fórmula de Arranjo:

$\mathsf{A_{n,~p}=\dfrac{n!}{(n-p)!}}$

Substituindo valores, vamos aos cálculos.

$\mathsf{A_{7,~3}+A_{4,~2}+A_{8,~4}=}\\\\ \mathsf{\dfrac{7!}{(7-3)!}+\dfrac{4!}{(4-2)!}+\dfrac{8!}{(8-4)!}=}\\\\\\ \mathsf{\dfrac{7\cdot6\cdot5\cdot4!}{4!}+\dfrac{4\cdot3\cdot2!}{2!}+\dfrac{8\cdot7\cdot6\cdot5\cdot4!}{4!}=}\\\\\\ \mathsf{(7\cdot6\cdot5)+(4\cdot3)+(8\cdot7\cdot6\cdot5)=}\\\\ \mathsf{210+12+1.680=}\\\\ \boxed{\mathsf{1.902}}$

Quaisquer dúvidas, deixe nos comentários.

Bons estudos$.$