Bonsoir,
Développer :
Double distributivité :
(a + b)(c + d) = ac + ad + bc + bd
A = (-3 - 2x)(4x - 5)
A = -3*4x + (-3)*(-5) + (-2x)*4x + (-2x)*(-5)
A = -12x + 15 - 8x² + 10x
A = -8x² - 12x + 10x + 15
A = -8x² - 2x + 15
✅
B = (2x² - 7)(x + 3x²)
B = 2x²*x + 2x²*3x² + (-7)*x + (-7)*3x²
B = 2x³ + 6x⁴ - 7x - 21x²
B = 6x⁴ + 2x³ - 21x² - 7x
✅
C = (4x - 7)²
C = (4x - 7)(4x - 7)
C = 4x*4x + 4x*(-7) + (-7)*4x + (-7)*(-7)
C = 16x² - 28x - 28x + 49
C = 16x² - 56x + 49
✅
Remarque :
On aura pu utiliser l'identité remarquable :
* = Multiplication
Bonne journée.
