| $$ \begin{aligned}36x^2+48xy+16x^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}52x^2+48xy\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{36x^2} +48xy+ \color{blue}{16x^2} = \color{blue}{52x^2} +48xy $$ |