(2x + 3y)(3x 4y) – 4(x - 2)(x + 3) (2y - 1)(2y + 1) (3 + 5x)(4 x) – Two Special Cases Perfect Square: Difference of two squares: (x + = (x = + 2ax + (x = a)2 + a)(x + a) x2 a2 - a)(x + a) x2 a2 – (2x - 3)2 = (2x 3)(2x 3) = 4x2 12x + 9 (x - 3)(x + 3) = 32 x2 – – – – = 9 x2 – EXERCISE B Multiply out 1. (x - 1)2 2. (3x + 5)2 3. (7x - 2)2 4. (x + 2)(x - 2) 5. (3x + 1)(3x - 1)
(2x + 3y)(3x – 4y) 4(x - 2)(x + 3) (2y - 1)(2y + 1) (3 + 5x)(4 – x) Two Special Cases Perfect Square: Difference of two squares: (x + a)2 = (x + a)(x + a) = x2 + 2ax + a2 (x - a)(x + a) = x2 – a2 (2x - 3)2 = (2x – 3)(2x – 3) = 4x2 – 12x + 9 (x - 3)(x + 3) = x2 – 32 = x2 – 9 EXERCISE B Multiply out 1. (x - 1)2 2. (3x + 5)2 3. (7x - 2)2 4. (x + 2)(x - 2) 5. (3x + 1)(3x - 1)