H =(x + 2)(6 + x) + (x + 2)(5 + x) I = (4x + 1)(3 - x) + (4x + 1)(7- x) J = (5 + x)(4x – 5) - (5 + x)(7 + x) K = (1 - x)(5x – 4) - (1 - x)(7 + x) Bonsoir aidez

H=x*6 + x*x + 2*6 + 2*x + x*5+x*x +2*5+2*x
= 6x + x^2 + 12 + 2x + 5x + x^2 + 10 + 2x
= 2x^2 + 15x + 22

I= 12x - 4x^2 + 3 - x + 28x - 4x^2 + 7 - x
= -8x^2 + 38x + 10

J= 20x - 25 + 4x^2 - 5x - 35 + 5x + 7x + x^2
= 5x^2 + 27x - 60

K= 5x -4 - 5x^2 + 4x - 7 + x -7x -x^2
= -6x^2 + 3x 11

Voila, en sachant que les ^2 veulent dire que c’est au carré