Bonjour,
[tex](x + 7)(x + 3)[/tex]
[tex] = {x}^{2} + 3x +7x + 21[/tex]
[tex] = {x}^{2} + 10x + 21[/tex]
[tex](x - 5)(x + 2)[/tex]
[tex] = {x}^{2} + 2x - 5x - 10[/tex]
[tex] = {x}^{2} - 3x - 10[/tex]
[tex](x - 3)(3x - 2)[/tex]
[tex] = 3 {x}^{2} - 2x - 9x + 6[/tex]
[tex] = 3 {x}^{2} - 11x + 6[/tex]
[tex](2x + 1)(x - 4)[/tex]
[tex] = 2 {x}^{2} - 8x + x - 4[/tex]
[tex] = 2 {x}^{2} - 7x - 4[/tex]
A=x*x+x*3+*x+7*3
A= x²+3x+7x+21
A=x²+10x+21
B=x*x+x*2-5*x-5*2
B=x²+2x-5x-10
B=x²-3x-10
D=x*3x-x*2-3*3x+3*2
D=3x²-2x-9x+6
D=3x²-11x+6
C=2x*x-2x*4+1*x-1*4
C=2x²-8x+1x-4
C=2x²-7x-4