| $$ \begin{aligned}(6x+8x)(x^2+3x^a+a^2)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}14x(x^2+3x^a+a^2)\end{aligned} $$ | |
| ① | Combine like terms: $$ \color{blue}{6x} + \color{blue}{8x} = \color{blue}{14x} $$ |