If h (x) = 6 - x, what is the value of (h*h) (10) ?

When you use the symbol * it is understood that the question is asking for the product of the function h (x) times h (x) evaluated at x = 10. Nevertheless, searching more context, I got the conclusion that this question refers to the composition of functions. In this case the right notation is (h o h) (10), which means h [h (x) ] at x = 10. In this latter case: h [ h (10) ] = h [6 - 10] = h ( - 4) = 6 - ( - 4) = 6 + 4 = 10. Answer: (h o h) (10) = 10.