$$ \begin{aligned}10xy(x^2y+xy)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}10x^3y^2+10x^2y^2\end{aligned} $$ | |
① | Multiply $ \color{blue}{10xy} $ by $ \left( x^2y+xy\right) $ $$ \color{blue}{10xy} \cdot \left( x^2y+xy\right) = 10x^3y^2+10x^2y^2 $$ |