Répondre :
1.
A = (x+3)(x-5)-(x-2)(x+5)
A = (x²-5x+3x-15) - (x²+5x-2x-10)
A = x² -2x -15 - x² -5x +2x +10
A = -5
2.
A = (x+3)(x-5)-(x-2)(x+5)
A = (x+3-x-2)(x-5)
A = 1(x-5)
A = (x-5)
3.
103x95-98x105 = 9785 - 10290 = -505
Voilà :)
A = (x+3)(x-5)-(x-2)(x+5)
A = (x²-5x+3x-15) - (x²+5x-2x-10)
A = x² -2x -15 - x² -5x +2x +10
A = -5
2.
A = (x+3)(x-5)-(x-2)(x+5)
A = (x+3-x-2)(x-5)
A = 1(x-5)
A = (x-5)
3.
103x95-98x105 = 9785 - 10290 = -505
Voilà :)