Answer:
(x - 9)(x + 9)
Step-by-step explanation:
x² - 81 ← is a difference of squares and factors in general as
a² - b² = (a - b)(a + b), then
x² - 81
= x² - 9²
= (x - 9)(x + 9)
2^2 ( 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) = 4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44,48
3^2(1,2,3, 5) = 9, 18, 27, 45
5^2(1, 2) = 25, 50
7^2 = 49
19 numbers
3b(3-b) is the answer
Step by step explanation : take out the most common factor which is 3b
