Tu développes chacune des expressions et tu en tires des conclusions
(3x+1)(2x-4)
= 3x*2x + 3x*(-4) + 1*2x + 1*(-4)
= 6x² - 12x + 2x - 4
= 6x² - 10x - 4
= f(x)
6(x-5/6)² - 49/6
= 6(x² - 10/6x + 25/36) - 49/6
= 6x² - 10x + 25/6 - 49/6
= 6x² - 10x - 24/6
= 6x ² - 10x - 4
= f(x)
