青云翻译

a is a constant, it does not change with the change of x and y, x and y how to change it every year to take place, but the cost is still the same.

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A is a constant, it not changes along with X and the Y change, no matter how X and Y does change, it must occur every year, moreover the expense is same.

A is a constant, it is not as Y X and change, no matter how Y X and change every year, and it is to occur, but the cost is still the same.

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