Répondre :
Pour x = 0, A = 0
pour x = -1/3, tu as : 9(-1/3)² -5 (-1/3) +1
= 9*1/9+ 5/3+1
= 9/9 + 15/9 + 9/9 = 33/9
pour x = 2/3, tu as 9(2/3)² -5*2/3 +1
= 9*4/9 -10/3 +1
= 36/9 - 10/3 +1
= 36/9 - 30/9 +9/9 = 15/9
On donne l'expression suivante : A: 9x²_5x + 1 Calculer la valeur numérique de A pour : 1. x : 0 2. x : _1 3. x : 2/3 ( deux tiers )
Pour x = 0, A = 0
pour x = -1/3, tu as : 9(-1/3)² -5 (-1/3) +1
= 9*1/9+ 5/3+1
= 9/9 + 15/9 + 9/9 = 33/9
pour x = 2/3, tu as 9(2/3)² -5*2/3 +1
= 9*4/9 -10/3 +1
= 36/9 - 10/3 +1
= 36/9 - 30/9 +9/9 = 15/9