You can see that we have
[tex]g(x)=f(x)-8[/tex]
This means that the two function differ by a constant, so they are "parallel", i.e. you get [tex]g(x)[/tex] by translating the graph of [tex]f(x)[/tex] 8 units down, and vice versa you get the graph of [tex]f(x)[/tex] by translating [tex]g(x)[/tex] 8 units up.
