Tap the blue circles to see an explanation.
| $$ \begin{aligned}(x-2)(x-3)(x-3)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}(x^2-3x-2x+6)(x-3) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}(x^2-5x+6)(x-3) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}x^3-3x^2-5x^2+15x+6x-18 \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}x^3-8x^2+21x-18\end{aligned} $$ | |
| ① | Multiply each term of $ \left( \color{blue}{x-2}\right) $ by each term in $ \left( x-3\right) $. $$ \left( \color{blue}{x-2}\right) \cdot \left( x-3\right) = x^2-3x-2x+6 $$ |
| ② | Combine like terms: $$ x^2 \color{blue}{-3x} \color{blue}{-2x} +6 = x^2 \color{blue}{-5x} +6 $$ |
| ③ | Multiply each term of $ \left( \color{blue}{x^2-5x+6}\right) $ by each term in $ \left( x-3\right) $. $$ \left( \color{blue}{x^2-5x+6}\right) \cdot \left( x-3\right) = x^3-3x^2-5x^2+15x+6x-18 $$ |
| ④ | Combine like terms: $$ x^3 \color{blue}{-3x^2} \color{blue}{-5x^2} + \color{red}{15x} + \color{red}{6x} -18 = x^3 \color{blue}{-8x^2} + \color{red}{21x} -18 $$ |