Let the sum of the first \(n\) terms of a non-constant A.P., \(a_{1},a_{2},a_{3},\ldots\ldots.\). be \(50n + \frac{n(n - 7)}{2}A\), where \(A\) is a constant. If \(d\) is the common difference of this A.P., then the ordered pair ( \(d,a_{50}\) ) is equal to