Question

factorise 9(2a – b) whole square – 4(2a – b)

Answer 1

Member since Dec 10 2008

Given 9(2a – b)2 – 4(2a – b) – 13

Put (2a – b) = k

Hence 9(2a – b)2 – 4(2a – b) – 13 = 9k2 – 4k – 13

= 9k2 – 13k + 9k – 13

= k(9k – 13) + 1(9k – 13)

= (9k – 13)(k + 1)

= [9(2a – b) – 13)[(2a – b) + 1]

= [18a – 9b – 13)[2a – b + 1]