The Total solution for NCERT class 6-12
x2 – 1 – 2 a – a2= x2 – (1 +2a + a2) – (x)2 –(1 + a)2 {∵ a2 –b2 = (a + b) (a – b)}= (x + 1 + a) (x – 1 – a)= (x + a + 1) (x – a – 1)