Question

the first term and the common difference of an A.P is 10000 and 2000 respectively. find the sum of the first 12 terms of A.P​

Answer 1

Step-by-step explanation:

a=t¹=10000

D (common difference)=t²-t¹=2000-10000=(-8000)

n=12

s(n) =n/2[2a+(n-1)D]

s¹²= 12/2[20000+(12-1) (-8000)

=6[−68000]

−408000

final answer is sum of the first 12 terms is -408000