Question

2n + 3 = 5

N/2 + 1 = 9

Answer 1

Hope This Helps

Explanation:

The common difference (d) = 2

The first element (a) = 3.

So, the n-th term is

I = a + (n-1).d

= 3 + (n-1)×2

= 1 + 2n.

So the required sum is

= (n/2)(a + I)

= (n/2)( 3 + 1 + 2n)

= (n/2)(4 + 2n)

= n (n+2)

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