Bonjour, voici la solution à la 1 ère question. Je n'ai pas compris les suivantes, navrés.
A = (3x+5)(2x+1)-(3x+1)
A = (3x × 2x + 3x + 5 × 2x + 5)-(3x+1)
A = (6x²+3x+10x+5)-(3x+1)
A = 6x²+13x+5 -3x -1
A = 6x²+10x+4 (ax² = 6x², bx = 10x, c = 4)
B = (4x-5)(2x+3)+3x+20
B = (4x × 2x + 4x * 3 -5 × 2x - 5 × 3) +3x+20
B = 8x²+12x-10x-15+3x+20
B = 8x²+5x+5
C = (5x+2)(3x+4)-(14x+2)
C = (5x × 3x + 5x * 4 + 2 × 3x + 2 × 4)-(14x+2)
C = (15x²+20x+6x+8)-(14x+2)
C = 15x²+26x+8-14x-2
C = 15x²+12x+6
D = (6x-5)(x+8)-(23x-50)
D = (6x × x + 6x × 8 -5 × x -5 × 8) -(23x-50)
D = (6x² + 48x -5x -40) -(23x-50)
D = 6x² + 43x -40-23x+50
D = 6x² +20x+10
En espérant t'avoir aidé.
