Question

a^2 - b^2 /a^2 - 2ab+b^2. a-b/a+b

Answer 1

(a^2-b^2/a^2-2ab+b^2).(a - b/a + b)
=(a - b)(a + b)/(a + b)^2 * (a - b)/(a + b)
=(a - b)^2/(a + b)^2
=a^2 - 2ab + b^2/a^2 + 2ab + b^2