Suppose a a∈I and the equation (x – a) (x – 5) = 3 has integral roots, then the set of values which a can take is:
ϕ
–11,–13
3,7
–3,–7
Let m∈I be a roots of (x−a)(x−5)=3, then
(m−a)(m−5)=3
As m-a and m-5 are integers, m-5=±1 or m-5=±3
⇒m=2,4,6,8
Thus, a=3,7