SOLUTION: the sum of the second and the fifth terms of an arithmetic sequence is 47,while the sum of the first eight terms is 116.Find the first two terms.thank you

Algebra ->  Sequences-and-series -> SOLUTION: the sum of the second and the fifth terms of an arithmetic sequence is 47,while the sum of the first eight terms is 116.Find the first two terms.thank you      Log On


   

Question 851718: the sum of the second and the fifth terms of an arithmetic sequence is 47,while the sum of the first eight terms is 116.Find the first two terms.thank you
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
2a + 5d=47,
116 = ½(2a + d(7))8
a = 46, d = -9
first two terms 46 and 37
2a + 5d=47,
116 = 4(2a + 7d)
116=8a+28d
2a + 5d=47
S = ½(92 -63)8
S=4*(29)
46,37,28,19, 10, 1, -8, 17
add to 116