Answer:
[tex]S_{n}[/tex] = [tex]\frac{n}{2}[/tex] (3n + 7)
Step-by-step explanation:
We require to find the first term a₁ and the common difference d
The n th term is given by 3n + 2, thus
a₁ = 3(1) + 2 = 3 + 2 = 5
a₂ = 3(2) + 2 = 6 + 2 = 8
d = 8 - 5 = 3
[tex]S_{n}[/tex] = [tex]\frac{n}{2}[/tex] [ 2a₁ + (n - 1)d ], substitute values
[tex]S_{n}[/tex] = [tex]\frac{n}{2}[/tex] [ (2 × 5) + 3(n - 1) ] = [tex]\frac{n}{2}[/tex] (10 + 3n - 3) = [tex]\frac{n}{2}[/tex] (3n + 7)
