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

$$ \begin{aligned} \left( \color{blue}{ 3a+3}\right) \cdot \left( \color{orangered}{ 3a-2}\right) &= \underbrace{ \color{blue}{3a} \cdot \color{orangered}{3a} }_{\text{FIRST}} + \underbrace{ \color{blue}{3a} \cdot \left( \color{orangered}{-2} \right) }_{\text{OUTER}} + \underbrace{ \color{blue}{3} \cdot \color{orangered}{3a} }_{\text{INNER}} + \underbrace{ \color{blue}{3} \cdot \left( \color{orangered}{-2} \right) }_{\text{LAST}} = \\ &= 9a^2 + \left( -6a\right) + 9a + \left( -6\right) = \\ &= 9a^2 + \left( -6a\right) + 9a + \left( -6\right) = \\ &= 9a^2+3a-6; \end{aligned} $$

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