Réponse :
Bonjour,
[tex]A = (3x + 1)(2 - 2x) - (5 - 4x)(x - 1)\\\\= 2(3x + 1)(1 - x) - (5 - 4x)(x - 1)\\\\= -2(3x + 1)(x - 1) - (5 - 4x)(x - 1)\\\\= (x - 1)[-2(3x + 1) - (5 - 4x)]\\\\= (x - 1)(-6x - 2 - 5 + 4x)\\\\= (x - 1)(-2x - 7)[/tex]
[tex]B = (2 - 3x)(3 + 2x) + (3x + 2)(-6x - 9)\\\\= (2 - 3x)(3 + 2x) + 3(3x + 2)(-2x - 3)\\\\= (2 - 3x)(3 + 2x) - 3(3x + 2)(2x + 3)\\\\= (2x + 3)[(2 - 3x) - 3(3x + 2)]\\\\= (2x + 3)(2 - 3x - 9x - 6)\\\\= (2x + 3)(-12x - 4)\\\\= -4(4x + 3)(3x + 1)[/tex]
[tex]C = (6x + 2)(2x + 3) + (9x + 3)^2\\\\= \dfrac{(9x + 3)}{1,5}(2x + 3) + (9x + 3)(9x + 3)\\\\= \dfrac{10}{15}(9x + 3)(2x + 3) + (9x + 3)(9x + 3)\\\\= (9x + 3)[\dfrac{2}{3}(2x+3) + (9x + 3)]\\\\= (9x + 3)(\dfrac{4}{3}x + 2 + 9x + 3)\\\\= (9x + 3)(\dfrac{31}{3}x+5)\\\\= 3(3x + 1)(\dfrac{31}{3}x + 5)[/tex]
[tex]D = (3x + 3)^2 - (x + 2)(5x + 4)\\\\= 9x^2 + 18x + 9 - 5x^2 - 4x - 10x - 8\\\\= 9x^2 - 5x^2 +18x - 4x - 10x + 9 - 8\\\\= 4x^2 + 4x + 1\\\\= (2x + 1)^2[/tex]
