Bonjour,
A = 2x(6x-1)+(5x+3)-(2x+4)
A = 2x×6x + 2x×(-1) + 5x + 3 - 2x-4
A = 12x^2 - 2x + 5x + 3 - 2x - 4
A = 12x^2 + x - 1
B = 6-(3x-4) + 5(4x-2)-(-8x+1)
B = 6 - 3x + 4 + 20x - 10 + 8x - 1
B = 25x - 1
C = 3x - 3(4x - 5) + (4x + 7) - 2(4x - 8)
C = 3x - 12x + 15 + 4x + 7 - 8x + 16
C = - 13x + 38
D, E, F à toi de jouer :)
