First of all, let's find a key word that might help us out. In this scenario, the word is more. The word more tells us that we'll need to use either addition or subtraction, so we can get rid of answer D. The problem already states that g represents the number of girls, so let's use b to represent the number of boys.
Here's the first expression we'll use to get to our answer:
g = b + 7
Now, we must subtract 7 from both sides, as we know this is what we must do when we have variables.
<em>7 - g</em> = b + 7
As you can see, we have our answer. C.) 7-g
Hope this answer helped you out.
