If you call x the total value of the sales, the sale over 12,000 will be: g(x) = 12,000 - x.
And the commission is 4.1% of that = 0.041 * (12,000 - x) = 0.041 * g(x)
So, if f(x) = 0.041x, to calculate the commission you first have to calculate g(x) = 12,000 - x, and the f(g(x))=0.041[12,000 - x].
Which leads you to the solution for the commission as [f o g] (x) = f (g(x)) = 0.041 (12,000 - x).
Answer: [ f o g] (x)
It wants expanded form and the distributive property (something like 2(5+6b), so I would think it wants something like 7(200+50+6). This way, you're multiplying 7 by each expanded part of the number, which you would do anyway when solving like normal. Please correct me if I'm wrong!
Solution:
The given equation is

Now we will factor the middle term as per the ac-method because the given equation is a quadratic equation.

12/30 = 18/45....cross multiply
(30)(18) = (12)(45)
540 = 540...proportional
another way to tell is to see if they are equivalent...because proportions are nothing but equivalent fractions.
12/30 = 2/5
18/45 = 2/5
so yes, they are proportional