Question

Find the sum of sixteen terms of an ap -1,-5,-9......

Answer 1

Here is ur answer my friend

Answer 2

Answer:

here is your answer friend :-

a = -1

d = (-5) - (-1)

= (-4)

and n = 16

therefore,

sn = n / 2 [2a + ( n - 1 )d ]

sn = 16/2 [ 2 (-1) + (16-1) (-4) ]

sn = 8 [ (-2) + 15(-4) ]

sn = 8 [ (-2) + (-60) ]

sn = 8 (-62)

sn = -496

therefore your answer must be -496.

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