Question

Factor 9s^2-64

Answer 1

(3s - 8)(3s + 8) the difference of 2 squares

Answer 2

it can be written as
(3s)^2 - (8)^2
now using the identity a^2 - b^2 = (a + b)(a - b) we get
9s^2-64 = (3s)^2 - (8)^2 = (3s + 8)(3s - 8)