g(x) is the square root function: g(x) = sqrt(x).
h(x) is the equation of a straight line: h(x) = 5x.
Then the composite function h( g(x) ) is 5(sqrt(x) ).
If the input to this function is 25 (as shown in the problem), the output of g(x) is 5. This 5 becomes the input of h(x) , which takes on the value 1.
So the answer here is h( g(25) ) = 1