Help please im so confused

A) All you have to do is multiply the two values you get for the outer rectangle.

- (3x+4)(3x-4). When you expand it, you simply get 9x^2 - 16. This is easy because it’s something called the difference of 2 squares. When there’s a plus and a minus of the same number in different brackets, this occurs.

B) It’s the same concept as A

- (x-3)(x+3) expand that and you get x^2 - 9

C) is worded much harder than it truly is.

It’s simple area of larger rectangle subtract area of smaller rectangle.

9x^2 - x^2 - 16 - 9 which is 8x^2-25

72 is the mode because it shows up the most number of times