![6x=84](https://img.qammunity.org/2023/formulas/mathematics/college/t6th4m01ce9ma2x1ki8r9qw993d3fro878.png)
1) In this question, a good knowledge of multiplication by 12 is enough to dismiss this equation and solve it in a pretty straightforward way.
2) Which number times 12 is not the one to the right of the equation?
We can tell by looking at them that:
![\begin{gathered} 6x=84 \\ 6(12)=84 \\ 72=84\text{ FALSE} \\ \\ 6x=84 \\ (6x)/(6)=(84)/(6) \\ x=14 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/gozw9n35yzj44ivzc8pqq9w1xy2nwn840m.png)
Thus, the equation in which x=12 is not the solution is:
![6x=84](https://img.qammunity.org/2023/formulas/mathematics/college/t6th4m01ce9ma2x1ki8r9qw993d3fro878.png)