- #1

bananaman13

- 2

- 0

**I don't understand on how to get the answer of a certain problem in arithmetic series.**

**formula/s:**

Arithmetic means

Arithmetic means

An=A1+ (n-1)d

Arithmetic series

Arithmetic series

Sn=n/2 (A1+An)

**I understand on how to get the terms to these but when finding for:**

Find A1 if,

S10= -20 , d= 4

&

Find S12 if, 2+5+8+...

**I couldn't quite grasp the idea on how to apply the formulas to these problems.**

Any help is appreciated. Thank you very much

Any help is appreciated. Thank you very much