Find the $n$th term of the arithmetic sequence $\{a_n\}$ whose initial term a and common difference $d$ are given below. What is the fifty$-$first term?

$a_1=7$;$d=\frac{1}{5}$

What is the nth term of the arithmetic sequence $\{a_n\}?$

$a_n=$

$($Simplify your answer. Use integers or fractions for any numbers in the expression.$)$

What is the fifty$-$first term?

$a_{51}=$

$($Type an integer or a simplified fraction.$)$