Question

Saberia me dizer qual é a resposta da 9 e da 10

Answer 1

(9)

C_n,2=C_3,1

n!/(n-2)!2!=3!/(3-1)!1!

(n-1).(n-2)!/(n-2)!2!=3.2!/2!1!

(n-1)/2!=3/1

(n-1)/2.1=3

(n-1)=2.(3)

n-1=6

n=6+1

n=7

s=[7]

(10)

(x+2)!/x!=4.(2x-1)

(x+2).(x+1).x!/x!=8x-4

(x+2).(x+1)=8x-4

x^2+3x+2=8x-4

x^2+3x-8x+2+4=0

x^2-5x+6=0

∆=b^2-4.a.c

∆=(-5)^2-4.(1).(6)

∆=25-24

∆=1

x'=5+1/2

x=6/2

x'=3

x"=5-1/2

x"=4/2

x"=2

s=[(2,3)]

x'+x"=3+2

x'+x"=5

alternativa "E"

espero ter ajudado!

boa tarde!