Réponse:
Bonsoir
1)
En gras, j'indique le facteur commun :
A= 2×(x-3) +3×(x-3)×(x-3)
A = (x-3)×[2 + 3×(x-3)]
A = (x-3)(2+3x-9)
A = (x-3)(3x-7)
B = a×a - 7×a
B = a×(a-7)
C = 3×x×x×y - 3×2×x×y×y
C = 3xy(x-2y)
D = 5×a×(a+b) - (a+b)×(a+b)
D = (a+b)×[5a - (a+b)]
D = (a+b)(5a - a - b)
D = (a+b)(4a - b)
2)
Pour x = -3
A = (-3)²-4×(-3)-11
A = 9 + 12 - 11
A = 9+1
A = 10
B = -(-3)² + 2×(-3) + 25
B = -9 - 6 + 25
B = -15 + 25
B = 10
Pour x = -3 on a A = B = 10
