Question 646268
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
arithmetic series
{{{S[n] =(n(a[1]+a[n]))/2}}}****
 -195 = n(-27 + -51)/2
 -195 =( -78/2)n
 -195/-39 = n
     5 = n
Note: {{{a[5]}}} = -27 + 4d = -51, d = -6
{-27,-33,-39,-45,-51}