a) \(f\left(-3\right)=0\Leftrightarrow\left(-6-3y+7\right)\left(-9+2y-1\right)=0\)
\(\Leftrightarrow\left(1-3y\right)\left(2y-10\right)=0\Leftrightarrow\left[\begin{matrix}y=\frac{1}{3}\\y=5\end{matrix}\right.\)
b) \(f\left(2\right)=0\Leftrightarrow\left(2x-6+7\right)\left(3x+4-1\right)=0\)
\(\Leftrightarrow3\left(2x-1\right)\left(x+1\right)=0\Leftrightarrow\left[\begin{matrix}x=\frac{1}{2}\\x=-1\end{matrix}\right.\)