Répondre :
(2x+1)(3-4x)
=6x-8x²+3-4x
=-8x²+2x+3
(-x+7)(3x-7)
=-3x²+7x+21x-49
=-3x²+28x-49
(4x-2)(5-x)
=20x-4x²-10+2x
=-4x²+22x-10
=6x-8x²+3-4x
=-8x²+2x+3
(-x+7)(3x-7)
=-3x²+7x+21x-49
=-3x²+28x-49
(4x-2)(5-x)
=20x-4x²-10+2x
=-4x²+22x-10
(2x+1)(3-4x)
6x-8x²+3-4x
-8x²+2x+3
(-x+7)(3x-7)
-3x²+7x+21x-49
-3x²+28x-49
(4x-2)(5-x)
20x-4x²-10+2x
-4x²+22x-10
6x-8x²+3-4x
-8x²+2x+3
(-x+7)(3x-7)
-3x²+7x+21x-49
-3x²+28x-49
(4x-2)(5-x)
20x-4x²-10+2x
-4x²+22x-10