Question

Hi, I need help here!
Here is my question for arithmetic sequence; With the formula, Sn=1/2 n(2a + (n- 1)d).
Find the sum of the first 10 terms of the sequence: -3, 2, 7, 12, 17, 22,...
Have anyone know the answer?

Answer 1

Answer:

a=-3

n=10

d=5

Step-by-step explanation:

s10=195

= 10/2[2(-3)+(10-1)5]

=5[(-6)+9*5]

=5[-6+45]

=5*39

=195