Given: ‘a’ is an integer. I. Given: a2=9 ⇒a=±3 It does not give a unique value ∴ I alone is not sufficient II. Given: a2+a=6 a2+a–6=0 (a+3(a–2)=0 a=–3 or 2. It does not give a unique solution. ∴ II alone in not sufficient. I & II Only ‘a’ = –3 can satisfy both the statements ∴ I & II together are sufficient.