Question

Calcule o decimo termo da PA (-6,1,8...) ?

Answer 1

$a_{n} = a_{1} + (n-1)r$
$a_{10}$  = -6 +(10-1)7
$a_{10}$ = -6+(9)7
$a_{10}$ = -6 + 63
$a_{10}$ = 57

Answer 2

an=?
a1=-6
r=7
n=10
an=a1(n-1)*r
an=-6+9*7
an=-6+63
an=57