Both the roots are positive
$\begin{aligned}
& D \geq 0 \
& 4(a-3)^2-4 \times 9(1-a) \geq 0 \
& a^2-6 a+9-9+9 a \geq 0 \
& a^2+3 a \geq 0 \
& a(a+3) \geq 0
\end{aligned}$
a∈(−∞,−3]∪[0,∞) ...(i)
−2ab>02(a−1)2(a−3)>0
a∈(−∞,1)∪(3,∞) ...(ii)
f(0)=9>0
Equation (i) ∩ (ii)
$\begin{aligned}
& a \in(-\infty,-3] \cup[0,1) \
& 2 \alpha+\beta+\gamma-6+0+1=7
\end{aligned}$