Réponse :
Explications étape par étape :
Bonsoir
G= (y + 7)²
G= y² + 2× y × 7 + 49
G = y² +14y + 49
H= (5x - 3)²
H = 25x² - 2 × 5x × 3 + 9
H = 25x² - 30 x + 9
I = (4 - 6x ) ²
I = 16 - 2 × 4 × 6x + 36x²
I = 16 - 48x + 36x²
J = (4y - 3/2)²
J = 16y² - 2 × 4y×3/2 + 9/4
J = 16y² - 12y + 9/4
K = (4a + 8)/4 - (2a - 3)(3a + 1)
K = 4(a + 2)/4 - (2a - 3)(3a + 1)
K = a + 2 - ( 6a² + 2a - 9a - 3)
K = a + 2 - ( 6a² -7a - 3)
K = a + 2 - 6a² + 7a + 3
K = - 6a² + 8a + 5