Question

encontre o vigésimo quinto do termo da P. A(3,8...)

Answer 1

an = a1 + ( n - 1 ) . r
a25 = 3 + ( 25 - 1 ) . 5
a25 = 3 + 24 . 5
a25 = 3 + 120
a25 = 123

Answer 2

$a_n=a_1+(n-1)\cdot r$

$a_{25}=3+(25-1)\cdot5$

$a_{25}=3+24\cdot5$

$a_{25}=3+120$

$\boxed{\boxed{a_{25}=123 }}$