Factorise 15(2x−y)2−16(2x−y)−15)
(10x−5y+3)(10x−5y−5)
Given 15(2x−y)2−16(2x−y)−15)
Taking (2x−y) as a , we have
15(2x−y)2−16(2x−y)−15)
= 15a2−16a−15
=15a2−25a+9a−15
= 5a(3a−5)+3(3a−5)
= (5a+3)(3a−5)
Subsituting a=2x−y , we have
= (5(2x−y)+3)(3(2x−y)−5)
= (10x−5y+3)(10x−5y−5)