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