Bonjour,
Identités remarquables :
(a + b)² = a² + 2ab + b²
(a - b)² = a² - 2ab + b²
(a + b)(a - b) = a² - b²
A = (2x - 4)(3x - 5) + (5x - 1)²
A = 2x * 3x + 2x * (-5) - 4 * 3x - 4 * (-5) + (5x)² - 2 * 5x * 1 + 1²
A = 6x² - 10x - 12x + 20 + 25x² - 10x + 1
A = 25x² + 6x² - 10x - 12x - 10x + 20 + 1
A = 31x² - 32x + 21
B = (3y - 7)(3y + 7) - (2y + 5)²
B = (3y)² - 7² - ((2y)² + 2 * 2y * 5 + 5²)
B = 9y² - 49 - (4y² + 20y + 25)
B = 9y² - 49 - 4y² - 20y - 25
B = 9y² - 4y² - 20y - 49 - 25
B = 5y² - 20y - 74
C = (5z + 2)² - (6z - 5)²
C = (5z)² + 2 * 5z * 2 + 2² - ((6z)² - 2 * 6z * 5 + 5²)
C = 25z² + 20z + 4 - (36z² - 60z + 25)
C = 25z² + 20z + 4 - 36z² + 60z - 25
C = 25z² - 36z² + 20z + 60z + 4 - 25
C = -11z² + 80z - 21
