Question

ache a soma dos 15 primeiros termos da p.a (5,10...)

Answer 1

Boa tarde

an=a1+(n-1).r

an = 5 + 14 . 5
an = 5 + 70
an = 75

formula soma:

s = (a1+an). n /2
s = (5+75).15/2
s = 80.15/2
s = 1200/2
s = 600

bons estudos!