The sum of first 9 terms of an arithmetic sequence and sum of next 8 terms are equal.common difference is 5. What's 9th term of this sequence?
Answers
Answered by
0
Answer:
80
Step-by-step explanation:
sumof first 9 terms; 9/2(2x1+8d)
sum of first 8 terms;8/2(2x1+7d)
by simplyfying,
2x1=80
x1=40
x9=40+8*5=80
Answered by
0
Answer:
80
Step-by-step explanation:
sum of first 9 terms =9÷2 (2×1+8d)
=4.5 ×2+8d
sum of 8 terms. = 8÷2 (2×1 +7d)
= 4×2+ 7d
2×1 = 80
x1 = 40
x9 = 40 +8×5
= 40 ×40 = 80
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