find function value f(x)=x

Answer 1

function value? do you mean values of f(x) at certain values of x?
if so, it just tells as that they have the same values, for instance,
at x = -1, f(x) = -1
at x = 0, f(x) = 0
at x = 5/2, f(x) = 5/2

so there,, :)