Tap the blue circles to see an explanation.
| $$ \begin{aligned}(y^2+2x)^4& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}y^8+8xy^6+24x^2y^4+32x^3y^2+16x^4\end{aligned} $$ | |
| ① | $$ (y^2+2x)^4 = (y^2+2x)^2 \cdot (y^2+2x)^2 $$ |
| ② | Find $ \left(y^2+2x\right)^2 $ using formula. $$ (A + B)^2 = \color{blue}{A^2} + 2 \cdot A \cdot B + \color{red}{B^2} $$where $ A = \color{blue}{ y^2 } $ and $ B = \color{red}{ 2x }$. $$ \begin{aligned}\left(y^2+2x\right)^2 = \color{blue}{\left( y^2 \right)^2} +2 \cdot y^2 \cdot 2x + \color{red}{\left( 2x \right)^2} = y^4+4xy^2+4x^2\end{aligned} $$ |
| ③ | Multiply each term of $ \left( \color{blue}{y^4+4xy^2+4x^2}\right) $ by each term in $ \left( y^4+4xy^2+4x^2\right) $. $$ \left( \color{blue}{y^4+4xy^2+4x^2}\right) \cdot \left( y^4+4xy^2+4x^2\right) = \\ = y^8+4xy^6+4x^2y^4+4xy^6+16x^2y^4+16x^3y^2+4x^2y^4+16x^3y^2+16x^4 $$ |
| ④ | Combine like terms: $$ y^8+ \color{blue}{4xy^6} + \color{red}{4x^2y^4} + \color{blue}{4xy^6} + \color{green}{16x^2y^4} + \color{orange}{16x^3y^2} + \color{green}{4x^2y^4} + \color{orange}{16x^3y^2} +16x^4 = \\ = y^8+ \color{blue}{8xy^6} + \color{green}{24x^2y^4} + \color{orange}{32x^3y^2} +16x^4 $$ |