Bonjour,
1)
A = (x + 2) (x + 3) + (x - 3)
A = x² + 3x + 2x + 6 + x - 3
A = x² + 6x + 3
B = (2x - 3)²
B = 4x² - 12x + 9
2)
A = x² + 6x + 3
A = 3² + 6 * 3 + 3
A = 9 + 18 + 3
A = 30
B = 4x² - 12x + 9
B = 4 * 3² - 12 * 3 + 9
B= 4 * 9 - 36 + 9
B = 9
3)
A = x² + 6x + 3
A = 1,5² + 6 * 1,5 + 3
A = 2,25 + 9 + 3
A = 14,25
B = 4x² - 12x + 9
B = 4 * 1,5² - 12 * 1,5 + 9
B = 4 * 2,25 - 18 + 9
B = 9 + 9 - 18
B = 0
