Tap the blue circles to see an explanation.
| $$ \begin{aligned}(x^2-2)(x^2-5)(x^2-8)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}(x^4-5x^2-2x^2+10)(x^2-8) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}(x^4-7x^2+10)(x^2-8) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}x^6-8x^4-7x^4+56x^2+10x^2-80 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}x^6-15x^4+66x^2-80\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{x^2-2}\right) $ by each term in $ \left( x^2-5\right) $. $$ \left( \color{blue}{x^2-2}\right) \cdot \left( x^2-5\right) = x^4-5x^2-2x^2+10 $$ |
| ② | Combine like terms: $$ x^4 \color{blue}{-5x^2} \color{blue}{-2x^2} +10 = x^4 \color{blue}{-7x^2} +10 $$ |
| ③ | Multiply each term of $ \left( \color{blue}{x^4-7x^2+10}\right) $ by each term in $ \left( x^2-8\right) $. $$ \left( \color{blue}{x^4-7x^2+10}\right) \cdot \left( x^2-8\right) = x^6-8x^4-7x^4+56x^2+10x^2-80 $$ |
| ④ | Combine like terms: $$ x^6 \color{blue}{-8x^4} \color{blue}{-7x^4} + \color{red}{56x^2} + \color{red}{10x^2} -80 = x^6 \color{blue}{-15x^4} + \color{red}{66x^2} -80 $$ |