Question

Sum of first n terms =3n²+5n. Write the sequence. What is the position 152 in the sequence?

Answer 1

Here
$sn = 3 {n} ^{2} + 5n \\ put \: n = 1 \\ a = 3 + 5 = 8 \\ put \: n = 2 \\ s2 = 12 + 10 = 22 \\ now \: we \: have \: a2 = 22 - 8 = 14 \\ d = 14 - 8 = 6 \\ the \: series \: is \: \\ 8 \: 14 \: 20...............$