Question 934750
The 14th term of a linear sequence is 96 while the 25th term is 173. 
14th:: a + 13d = 96
25th:: a + 24d = 173
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Substitute and solve for "d":
11d = 77
d = 7
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Solve for "a":
a + 13*7 = 96
a + 91 = 96
a = 5
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Find the 
a) 19th term:: a + 18d = 5+18*7 = 131
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b) sum of 13th and 56th terms
a+12d + a+55d = 2a + 67d = 10+469 = 479
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 c) sum of the first twenty terms
I'll leave that to you.
Cheers,
Stan H.
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