Question 944507
The common difference is {{{3}}}.
So,
{{{1=x+3(1-1)}}}
{{{x=1}}}
and the series is,
{{{a[n]=1+3(n-1)}}}
{{{a[n]=1+3n-3}}}
{{{a[n]=3n-2}}}
and
{{{S[10]=(n/2)(a[1]+a[10])=(10/2)(1+28)=5(29)=highlight(145)}}}