Question

For which equation would x = 12 not be a solution?12 x = 1448 x = 965 x = 606 x = 84

Answer 1

$6x=84$

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:

$\begin{gathered} 6x=84 \\ 6(12)=84 \\ 72=84\text{ FALSE} \\ \\ 6x=84 \\ \frac{6x}{6}=\frac{84}{6} \\ x=14 \end{gathered}$

Thus, the equation in which x=12 is not the solution is:

$6x=84$