Question

de a soma dos 24 termos da p.a 5,7,9

Answer 1

a1=5
r=2
a24=?
a24=5+(24-1).2
a24=5+23.2
a24=5+46
a24=51

Sn= (a1+an).n/2
S24= (5+51).24/2
S24=56.24/2
S24=1344/2
S24=672