Répondre :
A=3(x+6)+2
=3x+18+2
=3x+20
B=x(y-2)+xy
=xy-2x+xy
=2xy-2x
C=7x(x+2)-6x²
=7x²+14x-6x²
=x²+14x
D=9x(x²-6)+2x²
=9x³-54x+2x²
=9x³+2x²-54x
E=2x(3+5x)+8x(7-x)+4(x-1)
=6x+10x²+56x-8x²+4x-4
=2x²66x-4
=3x+18+2
=3x+20
B=x(y-2)+xy
=xy-2x+xy
=2xy-2x
C=7x(x+2)-6x²
=7x²+14x-6x²
=x²+14x
D=9x(x²-6)+2x²
=9x³-54x+2x²
=9x³+2x²-54x
E=2x(3+5x)+8x(7-x)+4(x-1)
=6x+10x²+56x-8x²+4x-4
=2x²66x-4