Bonjour,
Developper :
A = (2x - 9)(-3x + 5) - (-4x - 3)(7x - 6)
A = 2x*(-3x) + 2x*5 + (-9)*(-3x) + (-9)*5 - (-4x - 3)(7x - 6)
A = -6x² + 10x + 27x - 45 - (-4x - 3)(7x - 6)
A = -6x² + 37x - 45 - [-4x*7x + (-4x)*(-6) + (-3)*7x + (-3)*(-6)]
A = -6x² + 37x - 45 - ( -28x² + 24x - 21x + 18)
A = -6x² + 37x - 45 + 28x² - 24x + 21x - 18
A = -6x² + 28x² + 37x - 24x + 21x - 45 - 18
A = 22x² + 34x - 63
B = - (6x - 1)²
→ identité remarquable :
B = - [(6x)² - 2*6x*1 + 1²]
B = - (36x² - 12x + 1)
B = -36x² + 11x - 1
C = (-11x - 7)²
→ identité remarquable :
C = (-11x)² - 2*(-11x)*7 + 7²
C = 121x² - (-154x) + 49
C = 121x² + 154x + 49
D = (8x - 3)(8x + 3)
→ identité remarquable :
D = (8x)² - 3²
D = 64x² - 9
* = multiplication
Bonne journée.
