Answer:
n= (C/4) -9
Explanation:
The equation that in this problem describes the total charge for a trophy order with n lines of engraving is:

where
n is the number of lines of engraving
We want to re-arrange the equation to solve for n in terms of C. To do that, we proceed as follows:
1) First, we subtract 36 from both sides of the equation. We get:

2) Now, we divide by 4 both sides of the equation. We get:

3) Finally, we divide each of the terms on the right by 4. We get:

So the correct answer is
n= (C/4) -9