b. (2x+1)au carre -4 c. 25-(5x-4)au carré d. (x+1)au carré-4x au carré e. x au carré-(-2x+5)au carré f. 9x au carré-(2x-3)au carré FACTORISER CHAQUE EXPRESSION

b = (2x+1-2)(2x+1+2) =(2x-1)(2x+3)

c = 5² -(5x-4) = (5-5x+4)(5+5x-4) = (-5x+9)(5x+1)

d =(x+1-2x)(x+1+2x) =(-x+1)(3x+1)

e =(x+2x-5)(x-2x+5) =(3x-5)(-x+5)

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

b.)  (2x +1)^2 - 4
= 4x^2 + 4x + 1 - 4
 = 4x^2 + 4x -3

c.) 25 - (5x - 4)^2
   = 25 -( 25x^2 -40x +16)
   =25 -16 +40x - 25x^2
  =-25x^2 + 40x + 9
  
d.) (x + 1)^2 -(4x)^2
= x^2 + 2x + 1 - 16x^2
=-15x^2 + 2x + 1

e.) x^2 - (-2x + 5)^2
= x^2 -( 4x^2 - 20x + 25)
=-3x^2 + 20x -25

f.) (9x)^2 - (2x - 3)^2
=81x^2 - 4x^2 + 12x - 9
=77x^2  + 12x  - 9