Algebra form an arithamatic sequence is 5n+4 .find the sum of the first 20 terms
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Answer:
1130
Step-by-step explanation:
1st term = 5(1) + 4 = 9
20th term = 5(20) + 4 = 104
∵ Sₙ = (n/2) [a + l] , where l is last term
∴ S₂₀ = (20/2) [ 9 + 104
= 10 [113]
= 1130
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