Can anyone please help me with this?

for the function f(x) =1/x....f(x)is increasing on the interval(s) and f(x) is decreasing on the interval(s)???

Recall that f increases where f' > 0

f = 1/x
f' = -1/x^2

f' < 0 for all x ≠ 0

Think about the graph. It's a hyperbola, and is always decreasing, on both sides of the vertical asymptote at x=0.