| (1) | $$ \begin{align} (x+8)(x-8) &= x^2-8^2 \\ &= x^2-64 \end{align}$$ |
| (2) | $$ \begin{align} (3-a)(3+a) &= 3^2-a^2 \\ &= 9-a^2 \end{align}$$ |
| (3) | $$ \begin{align} (5x+1)(5x-1) &= 25x^2-1 \end{align}$$ |
| (4) | $$ \begin{align} (3x+2)(3x-2) &= 9x^2-4 \end{align}$$ |
| (5) | $$ \begin{align} \left( x-\frac{1}{3} \right) \left( x+\frac{1}{3} \right) &= x^2-\frac{1}{9} \end{align}$$ |
| (6) | $$ \begin{align} (a-6b)(a+6b) &= a^2-36b^2 \end{align}$$ |