To find h(k(x)), we have to replace the x-variable of h(x) with the function k(x).
Then, find k(h(x)) using the same process.
As you can observe, the functions obtained are not equal.
Therefore, h(k(x)) is not equal to k(h(x)).
Also, the functions h and k are not inverse functions because the coefficient 5 would be as a denominator.