$$ \begin{aligned}z(5z-3)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}5z^2-3z\end{aligned} $$ | |
① | Multiply $ \color{blue}{z} $ by $ \left( 5z-3\right) $ $$ \color{blue}{z} \cdot \left( 5z-3\right) = 5z^2-3z $$ |