#1**+1 **

We can first plug in the values of n, to find a pattern.

When n = 1, 2*1 - 1 = 1

When n = 2, 2*2 - 1 = 3

When n = 3, 2*3 - 1 = 5

...

When n = 15, 2*15 - 1 = 29

We see the pattern, 1, 3, 5, 7, ..., 29.

We find the sum 1 + 3 + 5 + ... + 29.

1 + 3 + ... n + 1 = n ^ 2

(29 - 1)^2 = 784

That is your final answer.

I hope this helped,

Gavin.

GYanggg May 1, 2018