bonsoir
A= ( x+3 ) – ( x+5 ) – ( x-7 )
a = x+3-x-5-x+7
a = -x +5
B= - ( a+4 ) + ( -a – 5 ) + ( 3 – a )
b = -a-4-a-5+3-a
b= -3a-6
C= - ( x²– x ) – ( x – 1 ) – ( 1 – x² )
c = -x²+x -x+1-1+x²
c = 0
D= x² – ( 3x² – 5x² ) + ( x² – 8x²) – 2x²
d = x²- (-2x²) +(-7x²) -2x²
d =x² +2x²-7x²-2x²
d = -6x²
E= 5x² – ( 3x – 2 ) + ( 7x² – 6 )
e = 5x² -3x+2+7x²-6
e = 12x²-3x-4
F= - ( 4 + 3x – 2x² ) – ( 4x – x² ) – ( x² – x )
f = -4 -3x+2x² -4x+x²-x²+x
f = 2x² -6x-4