Answer:
B but am not sure tho it's probably A
Step-by-step explanation:

Try putting it on a timeline. It makes more sense that way :)
Answer:
x² - 9
Step-by-step explanation:
A difference of squares has the form
a² - b²
Thus
x² - 9
= x² - 3² ← is a difference of squares
Number of bricks = 12
Height of full tower = 27 inches
Height of one brick =

= 2.25 inch
Well then the answer is
80 grams