Question

qual é o vigesimo terma da PA (3,8,...)

Answer 1

a20 = a1 + 19r
a20 = 3 + 19*(5)
a20 = 3 + 95
a20 = 98

Answer 2

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

$a_{20}=3+(20-1)\cdot5$

$a_{20}=3+19\cdot5$

$a_{20}=3+95$

$\boxed{\boxed{a_{20}=98}}$