Common difference of an arithmetic sequence is 7 and its 11th term 74.
a) What is its 10th term?
b) What is the sum of first 19 terms of this sequence ?
Answers
Answered by
1
Answer:
The tenth term is 67
The sum of first 19 terms is 130
Answered by
2
Answer:
a) 67 b) 1,273
Step-by-step explanation:
a11= 74
d = 7
74 = a +( 11-1) 7
74 = a + 70
a = 4
a) a10 = a + (10-1) 7
= 4 + 63
= 67
b) S19 = 19/2(2(4)+18(7))
= 19/2(134)
=19×67
= 1,273
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