Question

9(2a – b)2 – 4(2a – b) – 13

Answer 1

Here ,
=36a -18-8a-4b-13
=28a-4b-31

Answer 2

9(2a - b)2 - 4(2a - b) - 13
= (18a - 9b)2 - 8a + 4b - 13

= 36a - 18b - 8a + 4b -13
= 28a - 14b - 13