The difference of two squares can be expressed using the identity:
\[ a^2 - b^2 = (a - b)(a + b) \]
To apply this identity to the expression \(81 - 16\), we first identify \(a\) and \(b\). We notice that:
\[ 81 = 9^2 \quad \text{and} \quad 16 = 4^2 \]
Thus, we can rewrite \(81 - 16\) as:
\[ 81 - 16 = 9^2 - 4^2 \]
Now, we can apply the difference of squares identity:
\[ 9^2 - 4^2 = (9 - 4)(9 + 4) \]
Calculating the expressions gives:
\[ 9 - 4 = 5 \quad \text{and} \quad 9 + 4 = 13 \]
Therefore, we can write:
\[ 81 - 16 = (9 - 4)(9 + 4) = 5 \cdot 13 \]
So, the product equal to \(81 - 16\) is:
\[ 5 \cdot 13 \]
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