Tap the blue circles to see an explanation.
$$ \begin{aligned}(x-0)(x-10)(x-20)(x-40)(x-50)& \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle1}{\textcircled {1}} } }}}(x^2-10x+0x+0)(x-20)(x-40)(x-50) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle2}{\textcircled {2}} } }}}(x^2-10x)(x-20)(x-40)(x-50) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle3}{\textcircled {3}} } }}}(x^3-20x^2-10x^2+200x)(x-40)(x-50) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle4}{\textcircled {4}} } }}}(x^3-30x^2+200x)(x-40)(x-50) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle5}{\textcircled {5}} } }}}(x^4-40x^3-30x^3+1200x^2+200x^2-8000x)(x-50) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle6}{\textcircled {6}} } }}}(x^4-70x^3+1400x^2-8000x)(x-50) \xlongequal{ } \\[1 em] & \xlongequal{ \color{blue}{ \text{\normalsize{ \htmlClass{explanationCircle explanationCircle7}{\textcircled {7}} \htmlClass{explanationCircle explanationCircle8}{\textcircled {8}} } }}}x^5-120x^4+4900x^3-78000x^2+400000x\end{aligned} $$ | |
① | Multiply each term of $ \left( \color{blue}{x0}\right) $ by each term in $ \left( x-10\right) $. $$ \left( \color{blue}{x0}\right) \cdot \left( x-10\right) = x^2-10x0x0 $$ |
② | Combine like terms: $$ x^2 \color{blue}{-10x} \color{blue}{0x} 0 = x^2 \color{blue}{-10x} $$ |
③ | Multiply each term of $ \left( \color{blue}{x^2-10x}\right) $ by each term in $ \left( x-20\right) $. $$ \left( \color{blue}{x^2-10x}\right) \cdot \left( x-20\right) = x^3-20x^2-10x^2+200x $$ |
④ | Combine like terms: $$ x^3 \color{blue}{-20x^2} \color{blue}{-10x^2} +200x = x^3 \color{blue}{-30x^2} +200x $$ |
⑤ | Multiply each term of $ \left( \color{blue}{x^3-30x^2+200x}\right) $ by each term in $ \left( x-40\right) $. $$ \left( \color{blue}{x^3-30x^2+200x}\right) \cdot \left( x-40\right) = x^4-40x^3-30x^3+1200x^2+200x^2-8000x $$ |
⑥ | Combine like terms: $$ x^4 \color{blue}{-40x^3} \color{blue}{-30x^3} + \color{red}{1200x^2} + \color{red}{200x^2} -8000x = x^4 \color{blue}{-70x^3} + \color{red}{1400x^2} -8000x $$ |
⑦ | Multiply each term of $ \left( \color{blue}{x^4-70x^3+1400x^2-8000x}\right) $ by each term in $ \left( x-50\right) $. $$ \left( \color{blue}{x^4-70x^3+1400x^2-8000x}\right) \cdot \left( x-50\right) = \\ = x^5-50x^4-70x^4+3500x^3+1400x^3-70000x^2-8000x^2+400000x $$ |
⑧ | Combine like terms: $$ x^5 \color{blue}{-50x^4} \color{blue}{-70x^4} + \color{red}{3500x^3} + \color{red}{1400x^3} \color{green}{-70000x^2} \color{green}{-8000x^2} +400000x = \\ = x^5 \color{blue}{-120x^4} + \color{red}{4900x^3} \color{green}{-78000x^2} +400000x $$ |