It is known that the function f (x) is an even function on the set of real numbers R, and is a decreasing function on (0, + ∞). If x 10, then there is A.f（-x1）>f(-x2) B.f(-x1)=f(-x2) c.f(-x1)

A:
F (x) is an even function, f (- x) = f (x)
x> When 0, f (x) is a decreasing function
Then: x-x1 > 0
So: F (x2)

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