How do I use the following functions to answer the questions over the set of real numbers?

Question

I don't understand this question at all, I have to do it for a summer math packet that's due next week. I need to know the answer and how to get to it, thanks in advance. =)

Use the following functions to answer the questions over the set of real numbers: f(x)=-2x^2-7x 32, g(x)=2x 6/x-9, and h(x)=square root 4x 8

then the problems that I have to answer are

f(6) and g(h(7))

Answer 1

f(6) you can't really answer because you never put anything between the -7x and the 32, if the x is to multiply then use a different variable.

but for the second one its easy. Wait, you have to re-write out the functions. What is 4x 8 suppose to mean? Is it 4 times 8, or 4x(as the variable) then 8?

But to solve them is really easy. For f(6), just plug in 6 for all the variables then solve. And for g(h(7)), plug in 7 for all the variables in the h-function and get the answer. Then use the number you get and plug that in for all the variables in the g-function.