Multiply polynomial $ \, \color{blue}{ 5-x } \, $ by $ \, \color{orangered}{ x+6 }$.

$$ \left( \color{blue}{5-x} \right) \cdot \left( \color{orangered}{x+6} \right) = -x^2-x+30 $$

Step 1: First we have to write polynomials in descending order.

$$ \begin{aligned} P(x) &= -x+5 \\ Q(x) &= x+6 \\ \end{aligned} $$

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

$$ \begin{aligned} \left( \color{blue}{ -x+5}\right) \cdot \left( \color{orangered}{ x+6}\right) &= \underbrace{ \left( \color{blue}{-x} \right) \cdot \color{orangered}{x} }_{\text{FIRST}} + \underbrace{ \left( \color{blue}{-x} \right) \cdot \color{orangered}{6} }_{\text{OUTER}} + \underbrace{ \color{blue}{5} \cdot \color{orangered}{x} }_{\text{INNER}} + \underbrace{ \color{blue}{5} \cdot \color{orangered}{6} }_{\text{LAST}} = \\ &= -x^2 + \left( -6x\right) + 5x + 30 = \\ &= -x^2 + \left( -6x\right) + 5x + 30 = \\ &= -x^2-x+30; \end{aligned} $$

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