bonsoir =)
[tex]A=(x-3) (1-x) - (4-3x)(2x+3) \\ =x - x^{2} -3+3x -(8x+12-6 x^{2} -9x) \\ =x- x^{2} -3+3x-8x-12+6 x^{2} +9x \\ =- x^{2} +6 x^{2} +x+3x-8x+9x-3-12 \\ =5 x^{2} +5x-15[/tex]
[tex]B=(3-x)(x+3) - (7x-6)(-3+2x) \\ =3x +9 - x^{2} -3x - ( -21x+ 14 x^{2} + 18 -12x)
\\ = 3x -3x - x^{2} +9 + 21x -14 x^{2} -18 +12x
\\ = - x^{2} -14 x^{2} +21x+12x+9-18 \\ =-15 x^{2} + 33x -9[/tex]
voilà =)
