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