Bonjour
1)
N = (5x - 9)² - (3x + 4) (5x - 9)
N = 25x² - 90x + 81 - (15x² - 27x + 20x - 36)
N = 25x² - 90x + 81 - 15x² + 27x - 20x + 36
N = 25x² - 15x² - 90x - 20x + 27x + 81 + 36
N = 10x² - 83x + 117
2)
N = (5x - 9)² - (3x + 4) (5x - 9)
N = (5x - 9) [(5x - 9) - (3x + 4)]
N = (5x - 9) (5x - 9 - 3x - 4)
N = (5x - 9) (2x - 13)
3)
N = 10x² - 83x + 117
N = 10 * (- 2)² - 83 * (- 2) + 117
N = 10 * 4 + 166 + 117
N = 40 + 283
N = 323
4)
N = 10x² - 83x + 117
N = 10 * (- 4/3)² - 83 * (- 4/3) + 117
N = 10 * 16/9 + 332/3 + 117
N = 160/9 + 996/9 + 1 053/9
N = 2 209/9
