Hint: 1/3 and -2 are zero of (3x-1)(x+2).
You need the Remainder Theorem.
How's your Synthetic Division? Long division?
and are zeros of
where P is a polynomial of degree 2.
We can rewrite this way :
, but we don't care.
Since the first term is , a=1 because we would have 3x*x*ax˛ as the dominating term.
Let's study the constant term :
Now, you can develop...