To find the value of the expression x/(x+y) given the expression (1/(x-y) + 1/(x+y)), we can first simplify the given expression by finding a common denominator:

1/(x-y) + 1/(x+y) = (x+y + x-y)/(x-y)(x+y)
= (2x)/(x^2-y^2)
= 2x/(x^2-y^2)

Now we can simplify the expression x/(x+y):

x/(x+y) = x/(x+(x-y)) (since x+y = x + (x - y))
= x/(2x - y)
= x/(2x - y)

Therefore, the value of the expression x/(x+y) is x/(2x-y).