Répondre :
A=5(4x-7)+(x+9)(5x-6)
A=20x-35+5x²-6x+45x-54
A=5x²+59x-89
B=(x-5)(x+7)+(2x-4)(3x-1)
B=x²+7x-5x-35+6x²-2x-12x+4
B=7x²-12x-31
C=3x(x+2)-(2x+1)(x+5)
C=3x²+6x-(2x²+10x+x+5)
C=3x²+6x-2x²-10x-x-5
C=x²-5x-5
A=20x-35+5x²-6x+45x-54
A=5x²+59x-89
B=(x-5)(x+7)+(2x-4)(3x-1)
B=x²+7x-5x-35+6x²-2x-12x+4
B=7x²-12x-31
C=3x(x+2)-(2x+1)(x+5)
C=3x²+6x-(2x²+10x+x+5)
C=3x²+6x-2x²-10x-x-5
C=x²-5x-5