(x + 1)(x - 2) + (x + 2)(x - 3) =
= (x² - 2x + x - 2) + (x² - 3x + 2x - 6) =
= (x² - x - 2) + (x² - x - 6) =
= x² - x - 2 + x² - x - 6 = 2x² - 2x - 8
