$$ \begin{aligned}\frac{x-4}{3x\cdot2-12x}& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}\frac{x-4}{-6x}\end{aligned} $$ | |
① | $$ \color{blue}{6x} \color{blue}{-12x} = \color{blue}{-6x} $$ |