1. Multiply: (x + 4)(x – 4) = x2 – 4x + 4x – 16 = x2 – 16 Multiply: (2y + 3)(2y – 3) = 4y2 – 6y + 6y – 9 = 4y2 – 9 (a + b)(a – b) = a2 – b2 a2 – b2 = (a + b)(a – b) Difference of two squares

2. Factor . Factor w2– 49 = w2 – 72 = (w + 7)(w – 7) Example 5-1a

3. Factor . Factor = (6k)2 – (12m)2 = (6k + 12m)(6k – 12m) Example 5-1a

4. Factor Example 5-1a

5. Solve the equation by factoring. (m + 9)(m – 9)= 0 m + 9 = 0 or m – 9 = 0 m = -9 or m = 9

6. Solve the equation by factoring. 8x3 – 2x = 0 2x(4x2 – 1) = 0 2x(2x + 1)(2x – 1)= 0 2x = 0 or 2x + 1 = 0 or 2x – 1 = 0 x = 0 or 2x = -1 or 2x = 1 x = - ½ x = ½ {0, - ½ , ½ }