Réponse : (*)signifie <<multiplier par>>
1) D=3*x+3*7-2*x+1*x-8
=3x+21-2x+1x-8
=3x-2x+1x+21-8
=6x+29
=6*0+29
=0*29
=0
E= -6*x+-6*2-2*x-4*5*x-1
= -6x+-12-2x-20x-1
= -6x-6x-20x+-12-1
= 0x-20x+-11
= -20x+-11
= -20*0+-11
= 0+-11
= -11
F= x+1*x-1+-3*x+10
= x+1x-1+-3x+10
= x+1x+-3x-1+10
= 2x+-3x-1+10
= 1x-11
= 1*2-11
= 2-11
= -9