Tap the blue circles to see an explanation.
$$ \begin{aligned}(x-1)^2(x+1)^2(x-2)(x+2)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}(x^2-2x+1)(x^2+2x+1)(x-2)(x+2) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}(x^4-2x^2+1)(x-2)(x+2) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}(x^5-2x^4-2x^3+4x^2+x-2)(x+2) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle5}{\textcircled {5}} \htmlClass{explanationCircle explanationCircle6}{\textcircled {6}} } }}}x^6-6x^4+9x^2-4\end{aligned} $$ | |
① | Find $ \left(x-1\right)^2 $ using formula. $$ (A - B)^2 = \color{blue}{A^2} - 2 \cdot A \cdot B + \color{red}{B^2} $$where $ A = \color{blue}{ x } $ and $ B = \color{red}{ 1 }$. $$ \begin{aligned}\left(x-1\right)^2 = \color{blue}{x^2} -2 \cdot x \cdot 1 + \color{red}{1^2} = x^2-2x+1\end{aligned} $$Find $ \left(x+1\right)^2 $ using formula. $$ (A + B)^2 = \color{blue}{A^2} + 2 \cdot A \cdot B + \color{red}{B^2} $$where $ A = \color{blue}{ x } $ and $ B = \color{red}{ 1 }$. $$ \begin{aligned}\left(x+1\right)^2 = \color{blue}{x^2} +2 \cdot x \cdot 1 + \color{red}{1^2} = x^2+2x+1\end{aligned} $$ |
② | Multiply each term of $ \left( \color{blue}{x^2-2x+1}\right) $ by each term in $ \left( x^2+2x+1\right) $. $$ \left( \color{blue}{x^2-2x+1}\right) \cdot \left( x^2+2x+1\right) = \\ = x^4+ \cancel{2x^3}+x^2 -\cancel{2x^3}-4x^2 -\cancel{2x}+x^2+ \cancel{2x}+1 $$ |
③ | Combine like terms: $$ x^4+ \, \color{blue}{ \cancel{2x^3}} \,+ \color{green}{x^2} \, \color{blue}{ -\cancel{2x^3}} \, \color{orange}{-4x^2} \, \color{blue}{ -\cancel{2x}} \,+ \color{orange}{x^2} + \, \color{blue}{ \cancel{2x}} \,+1 = x^4 \color{orange}{-2x^2} +1 $$ |
④ | Multiply each term of $ \left( \color{blue}{x^4-2x^2+1}\right) $ by each term in $ \left( x-2\right) $. $$ \left( \color{blue}{x^4-2x^2+1}\right) \cdot \left( x-2\right) = x^5-2x^4-2x^3+4x^2+x-2 $$ |
⑤ | Multiply each term of $ \left( \color{blue}{x^5-2x^4-2x^3+4x^2+x-2}\right) $ by each term in $ \left( x+2\right) $. $$ \left( \color{blue}{x^5-2x^4-2x^3+4x^2+x-2}\right) \cdot \left( x+2\right) = \\ = x^6+ \cancel{2x^5} -\cancel{2x^5}-4x^4-2x^4 -\cancel{4x^3}+ \cancel{4x^3}+8x^2+x^2+ \cancel{2x} -\cancel{2x}-4 $$ |
⑥ | Combine like terms: $$ x^6+ \, \color{blue}{ \cancel{2x^5}} \, \, \color{blue}{ -\cancel{2x^5}} \, \color{green}{-4x^4} \color{green}{-2x^4} \, \color{orange}{ -\cancel{4x^3}} \,+ \, \color{orange}{ \cancel{4x^3}} \,+ \color{red}{8x^2} + \color{red}{x^2} + \, \color{green}{ \cancel{2x}} \, \, \color{green}{ -\cancel{2x}} \,-4 = x^6 \color{green}{-6x^4} + \color{red}{9x^2} -4 $$ |