Réponse :
Salut ,
A = 50 - (x + 20)
A=50-X-20
A=30-X
B = - (10 + x) + (x + 5)
B=-10-X+X+5
B=-5
C = (x² - 4x) - (5x² + 2x - 1)
C=X²-4X-5X²-2X+1
C=-4X²-6X+1
D = - (3 - x + x²) + (-2x +3x² - 8)
D=-3+X-X²-2X+3X²-8
D=-11-X+2X²
D=2X²-X-11
E = x - 4 - (2 + x) + (x + 5)
E=X-4-2-X+X+5
E=-1+X
F = - (x - 8) + (x - 6) - (7 - x)
F=-8+8+X-6-7+X
F=-5+X
G = (x² + 5x - 4) - (-2x² + 9x - 7)
G=X²+5X-4-2X²-9X+7
G=-X²-4X+3
Courage !
