Tap the blue circles to see an explanation.
| $$ \begin{aligned}(m+n)((m^2+n^2)^2+2mn^2(n-m))& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}(m+n)(1m^4+2m^2n^2+n^4+2mn^2(n-m)) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}(m+n)(1m^4+2m^2n^2+n^4+2mn^3-2m^2n^2) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}(m+n)(1m^4+2mn^3+n^4) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}m^5+2m^2n^3+mn^4+m^4n+2mn^4+n^5 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle5}{\textcircled {5}} } }}}m^5+m^4n+2m^2n^3+3mn^4+n^5\end{aligned} $$ | |
| ① | Find $ \left(m^2+n^2\right)^2 $ using formula. $$ (A + B)^2 = \color{blue}{A^2} + 2 \cdot A \cdot B + \color{red}{B^2} $$where $ A = \color{blue}{ m^2 } $ and $ B = \color{red}{ n^2 }$. $$ \begin{aligned}\left(m^2+n^2\right)^2 = \color{blue}{\left( m^2 \right)^2} +2 \cdot m^2 \cdot n^2 + \color{red}{\left( n^2 \right)^2} = m^4+2m^2n^2+n^4\end{aligned} $$ |
| ② | Multiply $ \color{blue}{2mn^2} $ by $ \left( n-m\right) $ $$ \color{blue}{2mn^2} \cdot \left( n-m\right) = 2mn^3-2m^2n^2 $$ |
| ③ | Combine like terms: $$ m^4+ \, \color{blue}{ \cancel{2m^2n^2}} \,+n^4+2mn^3 \, \color{blue}{ -\cancel{2m^2n^2}} \, = m^4+2mn^3+n^4 $$ |
| ④ | Multiply each term of $ \left( \color{blue}{m+n}\right) $ by each term in $ \left( m^4+2mn^3+n^4\right) $. $$ \left( \color{blue}{m+n}\right) \cdot \left( m^4+2mn^3+n^4\right) = m^5+2m^2n^3+mn^4+m^4n+2mn^4+n^5 $$ |
| ⑤ | Combine like terms: $$ m^5+2m^2n^3+ \color{blue}{mn^4} +m^4n+ \color{blue}{2mn^4} +n^5 = m^5+m^4n+2m^2n^3+ \color{blue}{3mn^4} +n^5 $$ |