Multiply polynomial $ \, \color{blue}{ x-5 } \, $ by $ \, \color{orangered}{ 2x+4 }$.

$$ \left( \color{blue}{x-5} \right) \cdot \left( \color{orangered}{2x+4} \right) = 2x^2-6x-20 $$

In this example we are multiplying two binomials so FOIL method can be used.

$$ \begin{aligned} \left( \color{blue}{ x-5}\right) \cdot \left( \color{orangered}{ 2x+4}\right) &= \underbrace{ \color{blue}{x} \cdot \color{orangered}{2x} }_{\text{FIRST}} + \underbrace{ \color{blue}{x} \cdot \color{orangered}{4} }_{\text{OUTER}} + \underbrace{ \left( \color{blue}{-5} \right) \cdot \color{orangered}{2x} }_{\text{INNER}} + \underbrace{ \left( \color{blue}{-5} \right) \cdot \color{orangered}{4} }_{\text{LAST}} = \\ &= 2x^2 + 4x + \left( -10x\right) + \left( -20\right) = \\ &= 2x^2 + 4x + \left( -10x\right) + \left( -20\right) = \\ &= 2x^2-6x-20; \end{aligned} $$

Polynomial Operations Calculator