Odpowiedź:
a)
P = (x - 6)(x + 3) = x² - 6x + 3x - 18 = x² - 3x - 18
b)
P = 1/2 * (x - 4)(x + 1) = 1/2(x² - 4x + x - 4) = 1/2(x² - 3x - 4) =
= 1/2x² - 3/2x - 2 = 1/2x² - (1 1/2)x - 2 = 0,5x² - 1,5x - 2
c)
P = 1/2 * (x + x + 3) * (x - 2) = 1/2(2x + 3)(x - 2) = 1/2(2x² + 3x - 4x - 6) =
= 1/2(2x² - x - 6) = x² - 1/2x - 3 = x² - 0,5x - 3