a) (x + 2)(x – 2) – (x – 3)(x + 1)
= x2 – 4 – (x2 + x – 3x – 3)
= x2 – 4 – x2 – x + 3x + 3
= 2x - 1
b) (2x + 1)2 + (3x – 1)2 + 2(2x + 1)(3x – 1)
= 4x2 + 4x + 9x2 – 6x + 1 + 2(6x2 – 2x + 3x – 1)
= 4x2 + 4x + 9x2 – 6x + 1 + 12x2 – 4x + 6x – 2
= 25x2 – 1