Step-by-step explanation:
Hey there!
The given series: -3,2,7,12,17,22.....
Common ratio (d) = t2-t1
= 2+3
= 5
No of terms (n) = 10
First term (a) = -3
Now;
[tex]sn = \frac{n}{2} (2a + (n - 1)d)[/tex]
Keeping all values we get;
[tex]s10 = \frac{10}{2} (2 \times - 3 + (10 - 1)5)[/tex]
Simplify it.
[tex]s10 = 5( - 6 + 45)[/tex]
or, S10 = 195.
Therefore, S10 = 195.
Hope it helps!
