Answers

2016-04-24T02:51:47+05:30
The last 2 terms of series are: (45-15+1)²= 31²  and -(43-15+1)²= -29²
Some of the components of the sum is cleared (from 43² to 31²), and will be following:
45² + 44²  - 30² - 29² = 2220.
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