Tap the blue circles to see an explanation.
| $$ \begin{aligned}2(3a^3+4)^2& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}2(9a^6+24a^3+16) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}18a^6+48a^3+32\end{aligned} $$ | |
| ① | Find $ \left(3a^3+4\right)^2 $ using formula. $$ (A + B)^2 = \color{blue}{A^2} + 2 \cdot A \cdot B + \color{red}{B^2} $$where $ A = \color{blue}{ 3a^3 } $ and $ B = \color{red}{ 4 }$. $$ \begin{aligned}\left(3a^3+4\right)^2 = \color{blue}{\left( 3a^3 \right)^2} +2 \cdot 3a^3 \cdot 4 + \color{red}{4^2} = 9a^6+24a^3+16\end{aligned} $$ |
| ② | Multiply $ \color{blue}{2} $ by $ \left( 9a^6+24a^3+16\right) $ $$ \color{blue}{2} \cdot \left( 9a^6+24a^3+16\right) = 18a^6+48a^3+32 $$ |