After observing the inequality, it is found that there is 2 x-5 (-x)
You can get the same form 2 a-5 (-a), so the constructor
F(x) = 2 x-5 (-x), so it is easy to judge that F(x) is the increasing function in R.
f(x)=2^x-5^(-x),f(-y)=2^(-y)-5^(y),
According to the condition f (x) < = f(-y), so x
x+y & lt; =0. choose B.