Bonjour,
A = 2x - (1 + x²) = 2x - 1 - x²
A = -x² + 2x - 1 ✔️
B = x² + (x + 7) = x² + x + 7 ✔️
C = 3 + (7x² - 2x) = 3 + 7x² - 2x
C = 7x² - 2x + 3 ✔️
D = 1 - (9x - x²) = 1 - 9x + x²
D = x² - 9x + 1 ✔️
Explications : 1 - 1 × (9x - x²) = 1 - 1 × 9x - 1 × (-x)² = 1 - 9x + x²
Bonne journée !
