i. p2 – q2
Here, a = p, b = q
∴ p2 – q2 = (p + q)(p – q) ….[(a2 – b2 ) = (a + b)(a – b)]
ii. 4x2 – 25y2
= (2x)2 – (5y)2
Here, a = 2x, b = 5y
∴ (2x)2 – (5y)2 = (2x + 5y)(2x – 5y) ….[(a2 – b2 ) = (a + b)(a – b)]
iii. y2 – 4
= y2 – 22
Here, a = y, b = 2
∴ y2 – 22 = (y + 2)(y – 2) ….[(a2 – b2 ) = (a + b)(a – b)]
iv P2 - 1/25
Here a = 1/25, b = 1/5
P2 - (1/5)2 = (P + 1/5) (p - 1/5) ... [(a2 - b2 ) = (a + b)(a - b)]
v. 9x2 - 1/16y2
Here a = 3x, b= 1/4y
∴ (3x)2 - (1/4y)2 = (3x + 1/4y)(3x - 1/4y) ….[(a2 – b2) = (a + b)(a – b)]