While both of these numbers are close to 7, 5.3 is the closest and we can find this out with subtraction. So, 9.9 - 7 = 2.9, but 7 - 5.3 = 1.7. Which one can we determine is closer? Well, 2.9 > 1.7, so our answer must be A. 5.3!
Why you may ask is 4x the GCF because when you divide 4x from both you're left with -4 + 3...... you can't take out the negative from the 16 because when you check your work negative 4x times 3 gives you negative 12x which isn't the equation you started with. So positive 4x times 3 give you 12x.