Question

determine o 20 termo da p.a (2,7,12,17...).​

Answer 1

Explicação passo-a-passo:

an = a1 + (n-1) .r

a20= 2 + (20-1).(7-2)

a20= 2 + 19.5

a20= 2+ 95

a20= 97

Answer 2

$\sf a_n=a_1+(n-1)\cdot\underbrace{\sf (a_2-a_1)}_{\sf r}$

$\sf a_{20}=2+(20-1)\cdot(7-2)$

$\sf a_{20}=2+19\cdot5$

$\sf a_{20}=2+95$

$\boxed{\boxed{\sf a_{20}=97}}$