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

$$ \begin{aligned} P(x) &= 8x+8 \\ Q(x) &= -8x+8 \\ \end{aligned} $$

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

$$ \begin{aligned} \left( \color{blue}{ 8x+8}\right) \cdot \left( \color{orangered}{ -8x+8}\right) &= \underbrace{ \color{blue}{8x} \cdot \left( \color{orangered}{-8x} \right) }_{\text{FIRST}} + \underbrace{ \color{blue}{8x} \cdot \color{orangered}{8} }_{\text{OUTER}} + \underbrace{ \color{blue}{8} \cdot \left( \color{orangered}{-8x} \right) }_{\text{INNER}} + \underbrace{ \color{blue}{8} \cdot \color{orangered}{8} }_{\text{LAST}} = \\ &= -64x^2 + 64x + \left( -64x\right) + 64 = \\ &= -64x^2 + 64x + \left( -64x\right) + 64 = \\ &= -64x^2+64; \end{aligned} $$

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