Bonsoir
A = 12x² + (4x + 5)²
A = 12x² + 16x² + 40x + 25
A = 28x² + 40x + 25
B = 7x - (6x + 2)²
B = 7x - (36x² + 24x + 4)
B = 7x - 36x² - 24x - 4
B = - 36x² - 17x - 4
C = - 16x² - (4x + 1) (4x - 1)
C = - 16x² - (16x² - 1)
C = - 16x² - 16x² + 1
C = - 32x² - 1
D = (6x - 4)² + (2x - 6)²
D = 24x² - 48x + 16 + 4x² - 24x + 36
D = 24x² + 4x² - 48x - 24x + 16 + 36
D = 28x² - 72x + 52.
