In Exercises \( 7-12 \), use a special product pattern to evaluate the expression. (See Example 2.) \( \begin{array}{lll}7.12^{2}-9^{2} & \text { (8) } 19^{2}-11^{2} & \text { 9. } 78^{2}-72^{2} \\ \begin{array}{lll}\text { 10. } 54^{2}-52^{2} & \text { 11. } 53^{2}-47^{2} & \text { (2.) } 39^{2}-36^{2}\end{array}\end{array}> \)

To evaluate expressions like \( 12^{2}-9^{2} \) using the special product pattern, remember the difference of squares formula, which states that \( a^{2} - b^{2} = (a-b)(a+b) \). For example, in \( 12^{2} - 9^{2} \), we have \( a = 12 \) and \( b = 9 \). Thus, it becomes \( (12 - 9)(12 + 9) = 3 \times 21 = 63 \). For the expression \( 19^{2} - 11^{2} \), apply the same principle. Here, \( a = 19 \) and \( b = 11 \), so \( (19 - 11)(19 + 11) = 8 \times 30 = 240 \). Using these patterns can simplify calculations and save you time when solving similar problems!