The x-intercepts are the points on the plot of a function f(x) where the graph crosses the x-axis. In other words, they're the values of x that make f(x) = 0.
In this case, the x-intercepts are the two roots of the parabola,
(x - 4) (x - 5) = 0 … … … (this is what the hint is referring to)
==> x - 4 = 0 or x - 5 = 0
==> x = 4 or x = 5
The intercepts themselves are points (x, f(x)), so you can report them as (4, 0) and (5, 0).