[tex]\begin{gathered} We\text{ have that }f(3)=6 \\ \text{ that means we must solve for b} \\ 3(3^2)-b(3)+12=6 \end{gathered}[/tex][tex]\begin{gathered} 3(3^2)-b(3)+12=6 \\ 3\cdot9-3b=6-12 \\ 27-3b=-6 \\ -3b=-6-27 \\ -3b=-33 \\ b=\frac{-33}{-3} \\ b=11 \end{gathered}[/tex]
