Answer
$${a_8} = 20$$
Work Step by Step
$$\eqalign{
& {a_1} = 6,\,\,\,d = 2 \cr
& {\text{The general term is}} \cr
& {a_n} = {a_1} + \left( {n - 1} \right)d \cr
& {a_n} = 6 + \left( {n - 1} \right)\left( 2 \right) \cr
& {a_n} = 6 + 2n - 2 \cr
& {a_n} = 2n + 4 \cr
& {\text{Finding }}{a_8} \cr
& {a_8} = 2\left( 8 \right) + 4 \cr
& {a_8} = 20 \cr} $$
