To determine the missing number:
[tex]\text{Let the missing number = x}[/tex][tex]\begin{gathered} 6\text{ times a number = 6x} \\ 6x+(-3)=9x \\ 6x-3=9x \end{gathered}[/tex]collect like terms
[tex]\begin{gathered} 6x-9x=3 \\ -3x=3 \\ \text{divide both side by -3} \\ -\frac{3x}{-3}=\frac{3}{-3} \\ x=-1 \end{gathered}[/tex]Therefore the missing number = -1
