Help,Question about multiplying functions

So I have the question:

f(x) = 3*2^x       h(x) = 2x-7       h(f (2)) = ???

I go through the steps of combining these functions:

Substitute: 2x-7(3*2^x(2))

Simplify: (2x-7)(6*4^x)

Distribute (FOIL): 12x+(8x^x)+-42+(-28^x)

h(f (2)) = 12x+(8x^x)+(-42)+(-28^x)

When I put in the answer the program says, "We could not understand your answer. Please check your answer for extra text or symbols" 

I don't know how to put this equation any simpler, can anyone help.