Bonjour.
3)
a) S = {2}
b) S = ]-(inf); 1]
c) S = ]0; +(inf)[
ex2:
1)
A = (2x-5)(-x+3) = -2x² + 6x + 5x - 15 = -2x² + 11x - 15
B = (x-2)(2+x) - (2x-1)² = x² - 4 - (4x² - 4x + 1) = -3x² + 4x - 5
C = (x²-x+1)(x+1) = x³ - x² + x + x² - x + 1 = x³ + 1
Bonne soirée.
