bjr

E = (2x + 3) - x (2x + 3)

comme k (a+b) = ka + kb on a

E = 2x + 3 - x*2x - x*3

E = 2x + 3 - 2x² - 3x

soit E = -2x² - x + 3

E = (2x + 3) - x (2x + 3)

facteur commun : 2x + 3

donc E = (2x + 3) (1 - x)

si x = -2/3

alors E = (2*(-2/3) + 3) (1 - (-2/3))

= (-4/3 + 3)*(3/3 + 2/3)

= (-4/3 + 9/3)*5/3

= 5/3 * 5/3 = 25/9

ou E = -2(-2/3)² - (-2/3) + 3

= -2*4/9 + 2/3 + 3

= -8/9 + 6/9 + 27/9 = 25/9