bonjour,
1/4 (x²-x) + 1/2x(x-1)-3(2/3 X² -1) =
((x²-x)/4 + (x²-x)/2 - (6x²/3 -3)=
(x²-x)/4 + (x²-x)/2 -(2x²-3) =
tt sous dénominateur 4 :
(x²-x)/4 + (2x²-2x)/4 -(8x²-12)/4 =
(x²-x+2x²-2x-8x²+12)/4 = (5x²-3x+12)/4
pour x = -1/2
[5*(-1/2)² -(3*-1/2) +12]/4 =
(5/4 +3/2 +12)/4=
(5/4 + 6/4 + 48/4)/4 =
59/9)/4 = 59/16