Factorise: 4a2−9b2−2a−3b
4a2−9b2−2a−3b=(2a)2–(3b)2–2a–3b=(2a–3b)(2a+3b)–1(2a+3b)=(2a+3b)[(2a–3b)–1]=(2a+3b)[2a–3b–1]