Factorisations : Exercice 2

f = (2x-1)(3x+2) - (4x+5)(2x-1)
f =(2x-1)(3x+2-4x-5)
f =(2x-1) ( -x -3)

g =64x²-49
g = (8x -7)(8x+7)

h = 21x²+7x
h = 7x(3x +1)

k = (4x-3)²  -(3x-4)²
k = (4x-3+3x-4)(4x-3 -3x+4)
k =(7x-7)(x +1)
k = 7(x-1)(x+1)

l = (3x-1)²  +(3x-1)(x+5)
l = (3x-1) (3x-1+x+5)
l =(3x-1)(4x+4)
l = 4(3x-1)(x+1)