\(X=10+12+14+...+98\)

\(X=\dfrac{98.45}{2}\)

\(X=2205\)

\(\dfrac{2}{5}\)+\(\dfrac{3}{5}\):\(\left(\dfrac{-9}{2}\right)\)+\(\dfrac{1}{2}\)

=\(\dfrac{2}{5}\)+\(\dfrac{3}{5}\).\(\left(\dfrac{-2}{9}\right)\)+\(\dfrac{1}{2}\)

=\(\dfrac{2}{5}\)+\(\left(\dfrac{-2}{15}\right)\)+\(\dfrac{1}{2}\)

=\(\dfrac{4}{15}\)+\(\dfrac{1}{2}\)

=\(\dfrac{23}{30}\)

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