# Sum solving

Algebra Level pending

The sum of a finite series can be calculated using the following formula.

$\displaystyle \sum_{a}^{n} d = na + \frac{dn(n-1)}{2}$

where $$n$$ is the number of terms, $$d$$ is the common difference and $$a$$ is the first term.

You are told that $$n = 56$$, $$d = 12$$ and $$\displaystyle\sum_{a}^{n} d = 296,016$$

Find $$a$$

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