Multiply each term of $ \left( \color{blue}{x+1}\right) $ by each term in $ \left( x-4\right) $.

$$ \left( \color{blue}{x+1}\right) \cdot \left( x-4\right) = x^2-4x+x-4 $$

Combine like terms:

$$ x^2 \color{blue}{-4x} + \color{blue}{x} -4 = x^2 \color{blue}{-3x} -4 $$

Multiply each term of $ \left( \color{blue}{x^2-3x-4}\right) $ by each term in $ \left( x-1\right) $.

$$ \left( \color{blue}{x^2-3x-4}\right) \cdot \left( x-1\right) = x^3-x^2-3x^2+3x-4x+4 $$

Combine like terms:

$$ x^3 \color{blue}{-x^2} \color{blue}{-3x^2} + \color{red}{3x} \color{red}{-4x} +4 = x^3 \color{blue}{-4x^2} \color{red}{-x} +4 $$

Multiply each term of $ \left( \color{blue}{x^3-4x^2-x+4}\right) $ by each term in $ \left( x-10\right) $.

$$ \left( \color{blue}{x^3-4x^2-x+4}\right) \cdot \left( x-10\right) = x^4-10x^3-4x^3+40x^2-x^2+10x+4x-40 $$

Combine like terms:

$$ x^4 \color{blue}{-10x^3} \color{blue}{-4x^3} + \color{red}{40x^2} \color{red}{-x^2} + \color{green}{10x} + \color{green}{4x} -40 = x^4 \color{blue}{-14x^3} + \color{red}{39x^2} + \color{green}{14x} -40 $$

Multiply each term of $ \left( \color{blue}{x^4-14x^3+39x^2+14x-40}\right) $ by each term in $ \left( x-12\right) $.

$$ \left( \color{blue}{x^4-14x^3+39x^2+14x-40}\right) \cdot \left( x-12\right) = \\ = x^5-12x^4-14x^4+168x^3+39x^3-468x^2+14x^2-168x-40x+480 $$

Combine like terms:

$$ x^5 \color{blue}{-12x^4} \color{blue}{-14x^4} + \color{red}{168x^3} + \color{red}{39x^3} \color{green}{-468x^2} + \color{green}{14x^2} \color{orange}{-168x} \color{orange}{-40x} +480 = \\ = x^5 \color{blue}{-26x^4} + \color{red}{207x^3} \color{green}{-454x^2} \color{orange}{-208x} +480 $$