Dévéloppe et réduis les expressions suivantes: A= 3(x+a)(x-3) B= 2(-3-t)(t-7) C= -(y+5)(3y-6) D= x(2x-6)(2-x)

A = (3x+3a)(x-3)

    = 3x²-9x+3ax-9a

B = (-6-2t)(t-7)

    = -6t+42-2t²+14t

    = -2t²+8t+42

C = -3y²+6y+15y-30

   = -3y²+21y-30

D = (2x²-6x)(2-x)

  = 4x²-2x^3-12x+6x²

= -2xcube +10x²-12x

A= 3.(x²-3x+ax-3a)

A= 3x²-9x+3ax-9a

B= (-6-2t)(t-7)

B= -6t+42-2t²+14t

B= 8t+42-2t²

C= (-y-5)(3y-6)

C= -3y²+6y-15y+30

C= -3y²-9y+30

D=(2x²-6x)(2-x)

D= 4x²-2x³-12x+6x²

D= 10x²-2x³-12x