Bonsoir,
[tex]B = (5x-9)^2-5x+9\\ B = (5x-9)^2-(5x-9)\\ B = (5x-9)\left[(5x-9)-1\right]\\ B = (5x-9)(5x-10)\\ B = 5(5x-9)(x-2)[/tex]
[tex]C = (3x+4)^2-3x-4\\ C = (3x+4)^2-(3x+4)\\ C = (3x+4)\left[(3x+4)-1\right]\\ C = (3x+4)(3x+3)\\ C = 3(3x+4)(x+1)[/tex]
[tex]D = (x+7)(3x-1)-3x+1+(3x-1)(x+4)\\ D = (x+7)(3x-1)-(3x-1)+(3x-1)(x+4)\\ D = (3x-1)\left[(x+7)-1+(x+4)\right]\\ D = (3x-1)(2x+10)\\ D = 2(3x-1)(x+5)[/tex]
