Factorization of (x - 2)(x + 2) + 3

(x - 2)(x + 2) + 3
= (x^2 - 2^2) + 3, since (A -B)(A + B) = A^2 - B^2
=  x^2 - 4 + 3
= x^2 - 1
= x^2 - 1^2, since 1^2 = 1
= (x - 1)(x + 1) Ans. using A^2 - B^2 = (A -B)(A + B)