$$ \begin{aligned}5(8v^2+7v-1)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}40v^2+35v-5\end{aligned} $$ | |
① | Multiply $ \color{blue}{5} $ by $ \left( 8v^2+7v-1\right) $ $$ \color{blue}{5} \cdot \left( 8v^2+7v-1\right) = 40v^2+35v-5 $$ |