Answer
$a_{1}=706;$
$a_{2}=712$
Work Step by Step
$a_{n}=a+\left( n-1\right) d\Rightarrow a_{50}=a+\left( 50-1\right) \times 6=1000\Rightarrow a=1000-49\times 6=706$
$d=6$
$a_{n}=a+\left( n-1\right) d\Rightarrow a_{1}=a+\left( 1-1\right) d=a=706;a_{2}=a+\left( 2-1\right) \times 6=706+6=712$
