Bonjour,
(5 - 3) (10 - 6) = 2 * 4 = 8
(5 - 3) (10 + 6) = 2 * 16 = 32
(x + 2) (x - 5) = x² - 5x + 2x - 10 = x² - 3x - 10
(x - 2) (x - 5) = x² - 5x - 2x + 10 = x² - 7x + 10.
25 - 10 = 5 (5 - 2)
6 + 20 = 2 (3 + 10)
10x + 35 = 5 (2x + 7)
14 - 21 = 7 (2 - 3)
9 - 27 = 9 (1 - 3)
21x - 14) = 7 (3x - 2).