Répondre :
F = (4x-1)(x+5) - (4x-1)²
= (4x-1)(x+5 - (4x-1))
= (4x-1)(x+5 -4x+1)
= (4x-1)(-3x + 6)
= 3(4x-1)(-x+2)
= (4x-1)(x+5 - (4x-1))
= (4x-1)(x+5 -4x+1)
= (4x-1)(-3x + 6)
= 3(4x-1)(-x+2)