So here, you just put in the value inside the parenthesis of the function into the actual function itself.
Here, for h(f(2)), the first one to put in is the one in f, which is 2.
Since f(x) = 3*2^x, and since x here is equal to 2, (because h(f(2)), we can just put in the 2 in place of the x.
3 * 2 ^ 2
And then you get:
3 * 4
Or 12.
So now you have
h(12)
Now do the same thing.
2 * 12 - 7
24 - 7
17
