$$ \begin{aligned}6 \cdot \frac{-1+5}{5}x& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}6\cdot\frac{4}{5}x\end{aligned} $$ | |
① | $$ \color{blue}{-1} + \color{blue}{5} = \color{blue}{4} $$ |