i. x2 - 1/x2
Here a = x, b = 1/x
x2 - (1/x)2 = (x + 1/x)(x - 1/x) ... [(a2 - b2 ) = (a + b)(a - b)]
ii. a2 b - ab
= a (ab - b)
= ab (a -1)
iii. 4x2 y - 6x2
= 2(2x2 y – 3x2 )
= 2x2 (2y – 3)
iv. 1/2y2 - 8z2

v. 2x2 - 8y2
= 2 (x2 – 4y2 )
= 2 [x2 – (2y)2 ]
= 2(x + 2y)(x – 2y) ….[(a2 – b2 ) = (a + b)(a – b)]