bonjour,
* = multiplier
A = 3(4x +2)
= 3*4x + 3*2
= 12x+6
B = x(2x - 4) + 4(-2X + 1)
= x*2x + x*-4 + 4*-2x + 4*1
= 2x²-4x-8x+4
= 2x²-12x+4
C = (8 - x)²
= (a-b)² = a²-2ab+b²( à savoir par coeur)
= 8²-2(8*x) +x²
= 64-16x+x²
D = (x + 2)(3x - 4)
= x*3x + x*-4 + 2*3x + 2*-
= ............
E = (2x + 1)( 1 + 2x)
fais D et E je corrigerais