# Probabilistic Expansion Part I

When the expression $$(2𝑥+𝑦)^{2014}$$ is expanded, two terms are selected at random. The probability that the sum of the coefficients of the two terms selected is even can be expressed as $$\frac{a}{b}$$, where $$a$$ and $$b$$ are positive integers. What is the value of $$b-a$$?

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