Répondre :
9x² + 6x + 1 = (3x + 1)²
on utilise (a + b)²
x² - 14x + 49 = (x - 7)²
on utilise (a - b)²
1 + 12x + 36x² = (6x + 1)²
on utilise (a + b)²
x² - 64 = (x - 8)(x + 8) on utilise (a - b)(a + b) 81 - x² = (9 - x)(9 + x) on utilise (a - b)(a + b) 25x² - 36 = (5x - 6)(5x + 6) on utilise (a - b)(a + b) 49x² - 4 = (7x - 2)(7x + 2) on utilise (a - b)(a + b) 1 - 16x² = (1 - 8x)(1 + 8x) on utilise (a - b)(a + b) 4x² - 9 = (4x - 9)(4x + 9) on utilise (a - b)(a + b)