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

$$ \begin{aligned} \left( \color{blue}{ 4g-4}\right) \cdot \left( \color{orangered}{ g+4}\right) &= \underbrace{ \color{blue}{4g} \cdot \color{orangered}{g} }_{\text{FIRST}} + \underbrace{ \color{blue}{4g} \cdot \color{orangered}{4} }_{\text{OUTER}} + \underbrace{ \left( \color{blue}{-4} \right) \cdot \color{orangered}{g} }_{\text{INNER}} + \underbrace{ \left( \color{blue}{-4} \right) \cdot \color{orangered}{4} }_{\text{LAST}} = \\ &= 4g^2 + 16g + \left( -4g\right) + \left( -16\right) = \\ &= 4g^2 + 16g + \left( -4g\right) + \left( -16\right) = \\ &= 4g^2+12g-16; \end{aligned} $$

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