Répondre :
A= 10x-5-4-6x x 8 10-5
= (10x-6x+x)+(-5-4+8+10-5)
= 5x+4
B= 8y 9x-8-2y-7x-4y 5x-8-6x
= (8y-2y-4y)+(9x-7x+5x-6x)+(-8-8)
= 2y+x-16
C= 10y 10y-2y-5 y-6-2x-9
= (10y+10y-2y+y)+(-2x)+(-5-6-9)
=19y-2x-20
D= -x 4 4 10y 9y-10y-8y 2y
= (-x)+(4+4)+(10y+9y-10y-8y+2y)
= -x+3y+8
et j'ai pas compris comment ordonner les expressions.