$$ \begin{aligned}w^3(3w^2+2w)+5^4& \xlongequal{ }w^3(3w^2+2w)+625 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}3w^5+2w^4+625\end{aligned} $$ | |
① | Multiply $ \color{blue}{w^3} $ by $ \left( 3w^2+2w\right) $ $$ \color{blue}{w^3} \cdot \left( 3w^2+2w\right) = 3w^5+2w^4 $$ |