A=(x+3)(2x-5)-(x+3)(5x-2)
A = (x+3) (2x-5-(5x-2))
A = (x+3) (-3x - 3)
A = -3 (x+3) (x+1)
C=(x-2)² - (2x-1)²
comme a² - b² = (a+b) (a-b) on aura
C = (x-2 + (2x-1)) (x-2 - (2x-1))
C = (3x - 3) (-x -1)
C = 3 (x-1) (-x-1)
D= (4x-1)² - 25
= (4x-1)² - 5²
idem a²-b² ...
= (4x-1+5) (4x-1-5)
= (4x+4) (4x-6)
= 8 (x+1) (2x-3)
B = a² - ab + b² = (a-b)² donc = (5x -2)²
