The area of what? if those are the dimensions of a triangle, you would do base times height divided by 2.
2^3 * 2^-5 = 2^(3 + (-5) = 2^(3 - 5) = 2^-2
It would be 21 because 7 times 3 equals 21 and the way you get that is 3 drawings per paper
Note: a² - b² = (a-b)(a+b)
9x² - 16y² = (3x)² - (4y)² = (3x - 4y)(3x + 4y)
