Question

qual o vigésimo termo da PA 3,8

Answer 1

$a_{1}=3\\ \\ r=8-3=5\\ \\ n=20\\ \\ \\ a_{n}=a_{1}+\left(n-1 \right )\cdot r\\ \\ a_{20}=a_{1}+\left(20-1 \right )\cdot r\\ \\ a_{20}=3+19\cdot 5\\ \\ a_{20}=3+95\\ \\ \boxed{a_{20}=98}$

Answer 2

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

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

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

$a_{20}=3+95$

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