| $$ \begin{aligned}x+12^{10}-2& \xlongequal{ }x+61917364224-2 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}x+61917364222\end{aligned} $$ | |
| ① | Combine like terms: $$ x+ \color{blue}{61917364224} \color{blue}{-2} = x+ \color{blue}{61917364222} $$ |