Question

(UnB) encontre o quinto termo da P.A. (8,x,4,...).

Answer 1

Resposta:

a₂-a₁=a₃-a₂   ==>x-8=4-x  ==>2x=12 ==>x=6

razão=r=a₂-a₁=a₃-a₂ =6-8=4-6=-2

aₙ=a₁+(n-1)*r

a₅=8+(5-1)*(-2)  =8-8 =0  é o quinto termo