What is the sum of 1st 30 terms of the arithmetic sequence 100,90,80,70,....
Answers
Answered by
0
Answer:
an=a+(n-1)d
a30=100+(29)10
=100+290
=390
Answered by
0
Answer:
(- 1350)
Step-by-step explanation:
a = 100
d = (- 10)
n = 30
Sum = n/2 [ 2a + (n-1)d]
= 30/2 [ 200 + (29)(-10)]
= 15 [200 - 290]
= 15 [- 90]
= - 1350
Please mark as the brainliest answer!!
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