x² + 2x - 3x - 6 + (2x+1)(3x-2) - 2x (x+1)
x² - x - 6 + (2x+1)(3x-2) - 2x (x+1)
x² - x - 6 + 6x² - x - 2 - 2x (x+1)
7x² - x - 6 - x - 2 - 2x (x+1)
7x² - 2x - 6 - 2 - 2x (x + 1)
7x² - 2x - 8 - 2x (x+1)
7x² - 2x - 8 - 2x² - 2x
5x² - 2x - 8 - 2x
= 5x² - 4x - 8.
