f(x) = (x + 1)/x
f(-1) = (-1 + 1)/(-1) = 0
f(1) = (1 + 1)/1 = 2
f(5) = (5 + 1)/5 = 6/5
f(5)/(f(1)+f(-1)) = 6/5 : (2 + 0) = 6/10 = 3/5
f(x) = (x + 1)/x
f(-1) = (-1 + 1)/(-1) = 0
f(1) = (1 + 1)/1 = 2
f(5) = (5 + 1)/5 = 6/5
f(5)/(f(1)+f(-1)) = 6/5 : (2 + 0) = 6/10 = 3/5